EVENT BOARDSIZE 19 SETUP W K17 O17 SETUP B D16 H17 Q16 Q14 COM Problem 1. Black to play. With the black stones on the left and on the right, White's three-space extension is vulnerable. Where should Black invade ? ENDCOM B 1 M17 USER CORRECT ANSWER ENDUSER COM Correct Answer. Black 1 is the vital point. No matter what White does after this, Black will have no problem. ENDCOM W 2 N16 COM If White plays 2, ... ENDCOM B 3 M16 COM ... Black pushes up with 3 and, ... ENDCOM W 4 M15 COM ... after 4, ... ENDCOM B 5 K16 COM ... attaches with 5. Black dominates the top. <= ENDCOM EVENT BOARDSIZE 19 SETUP W K16 O17 SETUP B D16 H17 Q16 Q14 MARK \t@K16 \t@H17 COM Problem 2. Black to play. White's marked stone is high, while Black's marked stone is lying in wait to gouge out White's base. What is the correct move for Black ? ENDCOM B 1 M17 USER CORRECT ANSWER ENDUSER COM Correct Answer. Black 1 is a strong invasion. It is the simplest way to play. <= ENDCOM VAR B 1 M16 USER ..CORRECT ANSWER ENDUSER COM Correct Answer. The high invasion of Black 1 is also correct, but it is more difficult. <= ENDCOM ENDVAR EVENT BOARDSIZE 19 SETUP W K16 O16 SETUP B D16 H17 Q16 Q14 COM Problem 3. Black to play. White has made a three-space extension along the fourth line. How should Black invade ? ENDCOM B 1 M16 USER CORRECT ANSWER ENDUSER COM Correct Answer. Invading on the fourth line with 1 is an effective move. It will now be hard for White to make sabaki when she attaches on the third line. <= ENDCOM VAR B 1 M17 COM Variation. Black plays on the third line with 1 because he wants to link up with his allies. ENDCOM W 2 M16 COM However, it will be easier for White to make sabaki when she attaches with 2. <= ENDCOM ENDVAR EVENT BOARDSIZE 19 SETUP W K17 K15 O17 SETUP B D16 H17 M17 Q16 Q14 MARK A@O15 1@K15 COM Problem 4. Black to play. How does Black answer the one-space jump of White 1 ? ENDCOM B 1 M15 USER CORRECT ANSWER ENDUSER COM Correct Answer. Simply jumping to 1 is adequate for Black. White is split into two groups. ENDCOM EVENT BOARDSIZE 19 SETUP W K16 M16 O17 SETUP B D16 H17 M17 Q16 Q14 R10 MARK 1@M16 COM Problem 5. Black to play. How does Black respond when White attaches on top with 1 ? ENDCOM B 1 L16 USER CORRECT ANSWER ENDUSER COM Correct Answer. Black should wedge in with 1. ENDCOM W 2 L15 VAR W 2 L17 COM Variation. White could also atari underneath with 2. ENDCOM B 3 L15 W 4 K17 B 5 N16 W 6 M18 B 7 M15 W 8 N17 COM White links up, but ... ENDCOM B 9 P10 COM ... Black makes a large-scale moyo on the right when he plays 9. <= ENDCOM ENDVAR B 3 L17 W 4 N16 B 5 K17 COM Up to 5, Black has gouged out White's base. Black is satisfied with this result. <= ENDCOM EVENT BOARDSIZE 19 SETUP W K16 M17 O16 SETUP B D16 H17 M16 Q16 Q14 MARK 1@M17 COM Problem 6. Black to play. White attaches underneath with 1. How should Black answer ? ENDCOM B 1 L17 USER CORRECT ANSWER ENDUSER COM Correct Answer. Black should hane at 1. ENDCOM W 2 L16 B 3 N17 W 4 M18 VAR W 4 M15 MARK 3@N17 COM Variation. If White answers 3 with 4, ... ENDCOM B 5 M18 COM ... Black captures with 5. ENDCOM W 6 N16 B 7 M17 MARK B@N15 A@L15 COM After connecting at 7, Black will aim at A or B. <= ENDCOM ENDVAR B 5 N16 W 6 N18 B 7 O17 MARK A@K17 COM A sharp exchange takes place up to 7. Black now threatens A. <= ENDCOM EVENT BOARDSIZE 19 SETUP W K17 L16 O17 SETUP B D16 H17 M17 Q16 Q14 MARK 1@L16 COM Problem 7. Black to play. White plays a diagonal move from the left. What is Black's response ? ENDCOM B 1 Q17 MARK \t@M17 USER CORRECT ANSWER ENDUSER COM Correct Answer. Taking the corner with Black 1 is enough. White must still deal with the marked black stone. ENDCOM W 2 M16 COM After White 2, ... ENDCOM B 3 O18 COM ...Black still has moves such as 3 to annoy White with. <= ENDCOM EVENT BOARDSIZE 19 SETUP W K16 M17 O17 SETUP B D16 M16 Q16 Q14 H17 MARK 1@M16 2@M17 COM Problem 8. Black to play. When Black makes the high invasion, White attaches underneath with 1. How does Black continue ? ENDCOM B 1 L17 USER CORRECT ANSWER ENDUSER COM Correct Answer. The moves from Black 1 ... ENDCOM W 2 L16 VAR W 2 K17 ENDVAR B 3 N17 VAR B 3 K17 COM Variation. Crawling to Black 3 can lead to complicated fighting. ENDCOM W 4 J17 B 5 J18 W 6 J16 B 7 K18 W 8 M15 COM After White ataris with 8, ... ENDCOM B 9 N16 W 10 P15 COM ... she peeps with 10. ENDCOM B 11 Q15 COM If Black connects at 11, ... ENDCOM W 12 N15 COM ... White plays 12, making very nice sabaki. <= ENDCOM ENDVAR W 4 M18 B 5 N16 COM ... to 5 are the simplest variation. ENDCOM W 6 N18 B 7 K17 W 8 J16 B 9 J17 COM White's stones have been separated into two groups, so Black can look forward to attacking them. <= ENDCOM EVENT BOARDSIZE 19 SETUP W K16 L16 M17 O16 SETUP B D16 H17 L17 M16 Q16 Q14 MARK 2@L16 1@L17 COM Problem 9.Black to play. If you didn't like the result in Problem 6, there's an even stronger way for Black to play. What is Black's strongest replay to White 2 ? ENDCOM B 1 M15 USER CORRECT ANSWER ENDUSER COM Correct Answer. Black 1 is a very strong move. ENDCOM W 2 N17 COM If White draws back to 2, ... ENDCOM VAR W 2 K17 COM Variation. Against White 2 ... ENDCOM B 3 N17 W 4 L18 COM ... and 4 ... ENDCOM B 5 M18 MARK 3@N17 COM ... Black plays 3 and 5, taking a big chunk of territory on the right. It is going to be very hard for White to make sabaki now. <= ENDCOM ENDVAR B 3 K17 COM ... Black links up to his allies on the left with 3. White's stones are now separated and Black has a superior position. <= ENDCOM EVENT BOARDSIZE 19 SETUP W K17 O17 R17 SETUP B D16 H17 M17 Q16 Q14 MARK 1@R17 COM Problem 10. Black to play. This time White has switched to the corner with an invasion at 1. How should Black respond ? ENDCOM B 1 Q17 USER CORRECT ANSWER ENDUSER COM Correct Answer. Black should let White live in the corner and make a wall on the outside. ENDCOM W 2 Q18 B 3 P18 VAR B 3 R16 COM Variation. If the right side is important to Black, he could Black with 3. ENDCOM W 4 S18 B 5 S17 W 6 R18 B 7 L16 COM Black ends with sente, so he can now switch to attacking the lone white stone at the center top with 7. <= ENDCOM ENDVAR W 4 R18 B 5 P17 W 6 S15 COM White's two stones at the top are outnumbered, so Black should easily make profit there. <= ENDCOM EVENT BOARDSIZE 19 SETUP W K17 O16 SETUP B D16 F17 Q15 R17 R10 COM Problem 11. Black to play. Again White has a three-space high extension, but the neighbouring black stones are on different points. How should Black play ? ENDCOM B 1 M17 USER CORRECT ANSWER ENDUSER COM Correct Answer. Black should make a deep invasion with 1. ENDCOM W 2 M16 COM This time, when White attaches with 2, ... ENDCOM B 3 N17 COM ... Black simply extends to 3, ... ENDCOM W 4 N16 B 5 P18 COM ... then jumps lightly to 5. ENDCOM W 6 L17 COM White must complete her shape with 6, so Black ends in sente. <= ENDCOM EVENT BOARDSIZE 19 SETUP W K16 O16 Q17 P17 SETUP B D16 H17 M16 R17 Q16 Q14 MARK \t@M16 3@P17 1@Q17 2@R17 COM Problem 12. Black to play. In response to Black's invasion with the marked stone, White plays 1 and 3. How should Black respond ? ENDCOM B 1 R18 USER CORRECT ANSWER ENDUSER COM Correct Answer. Black should simply descend to 1, taking the corner. White still cannot link up her stones. <= ENDCOM VAR B 1 M14 COM Failure. Black 1 is possible, but ... ENDCOM W 2 R18 COM ... after White 2, Black suffers a loss in the corner. <= ENDCOM ENDVAR EVENT BOARDSIZE 19 SETUP W K17 M18 O17 SETUP B D16 H17 M17 Q16 Q14 MARK 1@M18 COM Problem 13. Black to play. White attaches with 1. What should Black do ? ENDCOM B 1 N18 MARK B@K4 A@L18 USER CORRECT ANSWER ENDUSER COM Correct Answer. There are two Correct Answers: Black 1 and A. Black might even play elsewhere (B). <= ENDCOM VAR B 1 L18 USER CORRECT ANSWER ENDUSER COM Correct Answer. Also correct. <= ENDCOM ENDVAR VAR B 1 K4 W 2 M16 COM Variation. If Black played elsewhere, White might then attach from above with 2. ENDCOM B 3 P17 COM Black forces with 3 ... ENDCOM W 4 O16 B 5 O18 COM ... and 5, ... ENDCOM W 6 N18 COM ... then takes sente again. <= ENDCOM VAR W 6 N18 ENDVAR ENDVAR EVENT BOARDSIZE 19 SETUP W K17 P17 SETUP B D16 H17 R16 Q15 COM Problem 14. Black to play. White is overextended. Where should Black invade in this position ? ENDCOM B 1 M17 USER CORRECT ANSWER ENDUSER COM Correct Answer. Black 1 is the correct invasion point. ENDCOM W 2 P15 VAR W 2 K15 COM Failure for White. If White jumps to 2 with her stone on the left, ... ENDCOM B 3 O16 COM ... Black confines the white stone on the right with 3. White's play here is unsatisfactory. <= ENDCOM ENDVAR B 3 P14 W 4 O15 MARK 2@P15 COM If White plays 2 and 4, ... ENDCOM B 5 M15 COM ... Black jumps to 5. <= ENDCOM EVENT BOARDSIZE 19 SETUP W K16 M17 O16 P17 Q17 SETUP B D16 H17 M16 Q16 R17 R16 Q14 MARK \t@Q17 \t@P17 COM Problem 15. Black to play. Having played the marked stones, White returns to attach at 1. How should Black reply ? ENDCOM B 1 L17 USER CORRECT ANSWER ENDUSER COM Correct Answer. Black 1 is the vital point. ENDCOM VAR B 1 N17 COM Unsatisfactory. If Black hanes on the other side with 1, ... ENDCOM W 2 N16 B 3 L17 W 4 M18 B 5 L16 W 6 L18 COM ... White can make life at the top up to 6 ... ENDCOM B 7 K17 COM ... in sente. <= ENDCOM ENDVAR W 2 L16 B 3 N17 W 4 M18 B 5 N16 W 6 N18 B 7 K17 COM The exchange continues up to 7 and the white stones have become separated. Moreover, the white group at the top is still not completely alive. <= ENDCOM EVENT BOARDSIZE 19 SETUP W K17 M18 N17 O17 O18 SETUP B D16 H17 L18 N18 M17 Q16 Q14 MARK 2@N17 3@L18 1@N18 4@O18 B@R17 A@M16 COM Problem 16. Black to play. The moves to 3 are normal, but instead of A, White ataries with 4, aiming to invade the corner at B. How should Black answer ? ENDCOM B 1 Q18 USER CORRECT ANSWER ENDUSER COM Correct Answer. Defending the corner with 1 is best. ENDCOM W 2 L17 COM White next plays 2 and ... ENDCOM B 3 M19 W 4 M16 B 5 K18 W 6 M18 B 7 J17 COM ... the moves to 7 are natural. Black has no reason to be dissatisfied. <= ENDCOM EVENT BOARDSIZE 19 SETUP W K17 O15 P15 P17 Q14 SETUP B D16 H17 M15 M17 Q15 R16 P14 MARK A@Q16 1@Q14 COM Problem 17. Black to play. White cuts with 1. How should Black respond ? ENDCOM B 1 R14 USER CORRECT ANSWER ENDUSER COM Correct Answer. Black should atari with 1 and ... ENDCOM W 2 Q13 B 3 R13 W 4 Q12 B 5 R12 MARK 3@R13 COM ... take profit by crawling with 3 and 5. ENDCOM W 6 Q11 COM After White 6, ... ENDCOM B 7 M13 COM ... Black jumps to 7, and he dominates the top left. <= ENDCOM EVENT BOARDSIZE 19 SETUP W K16 O16 P17 Q17 O14 SETUP B D16 H17 M16 R17 R16 Q16 Q14 MARK 1@O14 COM Problem 18. Black to play. White jumps to 1. What is Black's strongest move ? ENDCOM B 1 L16 USER CORRECT ANSWER ENDUSER COM Correct Answer. Black should bump against the white stone with 1 and ... ENDCOM VAR B 1 M14 COM Failure. If Black simply jumps to 1, ... ENDCOM W 2 M17 COM ... White attaches with 2 and ... ENDCOM B 3 L17 W 4 L16 B 5 N17 W 6 M15 B 7 M18 W 8 N16 COM ... links up her stones with the moves to 8. <= ENDCOM ENDVAR W 2 K15 B 3 M14 COM ... then jump to 3. This is the strongest counter. <= ENDCOM EVENT BOARDSIZE 19 SETUP W K17 L17 M18 M16 N16 O17 SETUP B D16 H17 L18 M17 N17 N18 Q16 Q14 R10 MARK 6@N16 5@N17 4@M16 3@N18 2@L17 1@L18 COM Problem 19. Black to play. This time Black hanes from the other side and the moves continue to 6. What should Black do now ? ENDCOM B 1 O16 USER CORRECT ANSWER ENDUSER COM Correct Answer. Black 1 is a good move, ... ENDCOM W 2 O18 B 3 M19 W 4 Q17 VAR W 4 O19 COM Variation. If White wants to attack on the left, she will play 4 here. ENDCOM B 5 N19 W 6 K18 B 7 P17 W 8 O15 B 9 P16 MARK B@K19 A@J19 COM The moves continue up to 9, and Black gets a large profit in the corner. However, a white move at A or B, threatening Black's stones on the left and right, could later become troublesome. <= ENDCOM ENDVAR B 5 P16 W 6 R17 COM ... even when White can live in the corner with the moves to 6. ENDCOM B 7 K18 COM After Black 7, ... ENDCOM W 8 K15 MARK A@S16 COM ... White must fix up her shape by playing at 8, while Black A is sente. Black is satisfied with this result. <= ENDCOM EVENT BOARDSIZE 19 SETUP W J17 O17 SETUP B D16 G17 Q14 Q16 R11 COM Problem 20. Black to play. White has made a four-space extension along the top. Where should Black invade ? ENDCOM B 1 L17 USER CORRECT ANSWER ENDUSER COM Correct Answer. Black 1 is the vital point to invade. In this case, it is even better than A. ENDCOM VAR B 1 M17 MARK @@L17 COM Failure. @ is even better. <= ENDCOM ENDVAR W 2 J15 COM If White jumps to 2, ... ENDCOM B 3 L15 COM ... Black follows with 3. ENDCOM W 4 N15 B 5 L13 COM After 5, Black can attack on the left or the right. <= ENDCOM EVENT BOARDSIZE 19 SETUP W J17 O16 O17 SETUP B D16 G17 P17 Q16 Q14 COM Problem 21. Black to play. Even when White has the two stones on the right, the four-space extension is a bit wide. Where does Black invade ? ENDCOM B 1 M16 USER CORRECT ANSWER ENDUSER COM Correct Answer. Black 1 shows good go sense. ENDCOM VAR B 1 M17 USER CORRECT ANSWER ENDUSER COM Correct Answer. Black could also invade deeply with 1. ENDCOM W 2 L16 B 3 N15 W 4 N16 MARK 2@L16 COM However, White can confine Black to the side with 2 and 4. ENDCOM B 5 M16 W 6 M15 COM This will lead to an all-out fight. <= ENDCOM ENDVAR W 2 M18 COM If White tries to link up her stones with 2, ... ENDCOM B 3 L17 W 4 L18 B 5 K17 W 6 K18 B 7 J16 COM ... Black presses her in a low position with the moves to 7. <= ENDCOM EVENT BOARDSIZE 19 SETUP W K17 O17 Q17 SETUP B D16 H17 M17 Q16 Q14 MARK 1@Q17 COM Problem 22. Black to play. How does Black respond to White's attachment at 1 ? ENDCOM B 1 R17 USER CORRECT ANSWER ENDUSER COM Correct Answer. Black 1 ... ENDCOM W 2 P16 B 3 Q15 COM ... and 3 are a simple way of playing. Later, ... ENDCOM VAR B 3 Q18 COM Variation. Black 3 here is very strong, but it becomes very complicated. <= ENDCOM ENDVAR W 4 R18 COM ... White can start a ko by playing 4 ... ENDCOM B 5 Q18 W 6 P18 COM ... and 6. <= ENDCOM B 7 P17 EVENT BOARDSIZE 19 SETUP W J17 L16 M17 O17 SETUP B D16 G17 L17 M16 Q17 Q16 R13 MARK 4@M17 3@M16 2@L16 1@L17 COM Problem 23. Black to play. Against Black's invasion, White attaches at 2 and cuts with 4. How should Black respond ? ENDCOM B 1 K16 USER CORRECT ANSWER ENDUSER COM Correct Answer. Black is strong on the right, so Black 1 ... ENDCOM VAR B 1 N17 USER CORRECT ANSWER ENDUSER COM Correct Answer. Black 1 ... ENDCOM W 2 M18 B 3 M15 COM ... and 3 are a nice tesuji. ENDCOM W 4 N18 B 5 K16 W 6 L18 B 7 L15 COM Black gets a nice ponnuki in the center of the board with the moves to 7. <= ENDCOM ENDVAR W 2 L15 B 3 K17 COM ... and 3 are best. White's position on the right still has defects, but Black is strong on both sides. <= ENDCOM EVENT BOARDSIZE 19 SETUP W C14 C11 J17 J15 O17 O16 SETUP B C16 D16 G17 G15 P17 Q16 Q14 MARK \t@J15 \t@G15 COM Problem 24. Black to play. White and Black have exchanged the marked stones. Where is Black's invasion point now ? ENDCOM B 1 K16 USER CORRECT ANSWER ENDUSER COM Correct Answer. Black should first peep at 1, ... ENDCOM VAR B 1 L17 COM Failure. Invading deeply at 1 could be disastrous for Black ... ENDCOM W 2 L15 COM ... after White caps with 2. <= ENDCOM ENDVAR W 2 J16 B 3 M16 COM ... then play on the vital point of 3. ENDCOM W 4 O14 COM When White jumps to 4, ... ENDCOM B 5 M14 COM ... Black jumps to 5. Black can now attach on either the left or the right. <= ENDCOM EVENT BOARDSIZE 19 SETUP W K17 O17 O16 SETUP B D16 H17 P17 Q16 Q14 COM Problem 25. Black to play. White has made an ideal extension from her two stones on the right. However, it is still possible to invade this position. Where does Black play ? ENDCOM B 1 M17 USER CORRECT ANSWER ENDUSER COM Correct Answer. Black should invade at 1. ENDCOM W 2 M16 COM If White attaches at 2, ... ENDCOM VAR W 2 M18 COM Variation. If White attached underneath with 2, ... ENDCOM B 3 N18 W 4 N17 B 5 L18 W 6 M16 B 7 L17 W 8 L16 VAR W 8 O18 COM If White 8 here, ... ENDCOM B 9 L16 COM ... Black plays 9. Either way, Black is satisfied. <= ENDCOM ENDVAR B 9 O18 COM ... Black would play the moves to 9. <= ENDCOM ENDVAR B 3 L17 W 4 L16 B 5 K18 MARK 3@L17 COM ... Black links up to his allies on the left with 3 and 5. <= ENDCOM EVENT BOARDSIZE 19 SETUP W F17 K16 O17 SETUP B D16 D14 Q16 Q14 COM Problem 26. Black to play. White's position is impressive but it is yet no territory. Where should Black invade ? ENDCOM B 1 M17 MARK A@H17 USER CORRECT ANSWER ENDUSER COM Correct Answer. Black invades with 1. Since the position is symmetrical, he could just as well have invaded at A. ENDCOM VAR B 1 H17 USER CORRECT ANSWER ENDUSER COM Correct Answer. Also correct. <= ENDCOM ENDVAR W 2 N16 B 3 H17 W 4 G16 MARK 2@N16 COM If White responds with the diagonal moves at 2 and 4, ... ENDCOM B 5 K17 COM ... Black attaches at 5. Black is firmly established at the top. <= ENDCOM EVENT BOARDSIZE 19 SETUP W J17 N16 O17 P16 SETUP B D16 G17 P17 Q17 R16 R14 MARK A@J15 COM Problem 27. Black to play. Black attacks with the marked stone, aiming to invade. If White doesn't defend by playing A, where does Black invade ? ENDCOM B 1 M17 MARK A@O18 USER CORRECT ANSWER ENDUSER COM Correct Answer. Black 1 is the vital point. Black threatens to link up with his stones on the right by playing at A. ENDCOM VAR B 1 L17 COM Failure. An invasion at Black 1 is also possible, but ... ENDCOM W 2 K16 B 3 L16 W 4 L15 B 5 J18 W 6 H18 B 7 K18 W 8 H17 B 9 G18 W 10 M15 B 11 H19 W 12 H15 COM ... with the moves to 12, White gets a thick shape in the center of the board. <= ENDCOM ENDVAR W 2 N18 COM White must defend at 2. <= ENDCOM EVENT BOARDSIZE 19 SETUP W K17 L16 O17 O16 SETUP B D16 H17 M17 P17 Q16 Q14 MARK 2@L16 1@M17 COM Problem 28. Black to play. White counters Black's invasion with the diagonal move of 2. How does Black respond ? ENDCOM B 1 M16 USER CORRECT ANSWER ENDUSER COM Correct Answer. Black plays 1 and ... ENDCOM W 2 M15 B 3 N15 COM ... cuts with 3. ENDCOM VAR B 3 L15 COM Variation. Black can also cut at 3 here. ENDCOM W 4 K15 B 5 L14 W 6 N15 B 7 M18 MARK 6@N15 4@K15 COM After White plays 4 and 6, Black again descends to 7. <= ENDCOM ENDVAR W 4 N16 B 5 M18 MARK B@O18 A@K18 COM Black 5 is a steady move, threatening to link up his stones at A or B. <= ENDCOM VAR B 5 L15 COM Black 5 here is also possible. <= ENDCOM ENDVAR EVENT BOARDSIZE 19 SETUP W F17 K16 O17 M16 SETUP B D16 D14 Q16 Q14 M17 MARK 2@M16 1@M17 COM Problem 29. Black to play. What should Black do when White attaches at 2 ? ENDCOM B 1 L16 USER CORRECT ANSWER ENDUSER COM Correct Answer. Against White's attachment you should remember Black's wedge in at 1. This is Black's strongest reply. ENDCOM W 2 L15 COM If White blocks at 2, ENDCOM B 3 L17 W 4 N16 B 5 K17 W 6 J16 B 7 H18 W 8 G16 B 9 N18 COM ... Black lives up to 9 and ... ENDCOM W 10 O18 B 11 Q18 COM ... takes the corner with 11. White's compensation is her wall in the center, but it has cutting points at which Black can aim. <= ENDCOM EVENT BOARDSIZE 19 SETUP W J17 N16 O17 P16 N18 SETUP B D16 G17 M17 P17 Q17 R16 R14 MARK \t@N18 COM Problem 30. Black to play. After White plays the marked stone, how should Black continue ? ENDCOM B 1 K16 USER CORRECT ANSWER ENDUSER COM Correct Answer. There are two Correct Answers. Black plays 1 here if he wants outside thickness. <= ENDCOM VAR B 1 K18 USER CORRECT ANSWER ENDUSER COM Correct Answer. If Black wants to link up to his stones on the left, he will play 1 on the second line. <= ENDCOM ENDVAR EVENT BOARDSIZE 19 SETUP W K17 O17 Q18 SETUP B D16 G17 Q16 R17 Q14 COM Problem 31. Black to play. The white stones are overextended. Black has to attack now. How should he play ? ENDCOM B 1 M17 USER CORRECT ANSWER ENDUSER COM Correct Answer. Black 1 is the invasion point. This urgent move takes priority over all others. ENDCOM W 2 M18 COM If White attaches with 2, ... ENDCOM B 3 L18 W 4 L17 B 5 N18 MARK 3@L18 COM ... Black plays 3 and 5. ENDCOM W 6 M16 COM White tries to link up with 6 to ... ENDCOM B 7 N17 W 8 N16 B 9 O18 W 10 P17 COM ... 10, but ... ENDCOM B 11 O16 COM ... Black cuts with 11, catching three white stones. <= ENDCOM EVENT BOARDSIZE 19 SETUP W F17 K16 O17 M16 K15 L17 SETUP B D16 D14 Q16 Q14 M17 L16 L15 MARK 2@M16 1@M17 6@K15 5@L15 4@L17 3@L16 COM Problem 32. Black to play. When Black wedges in with 3, White ataris from underneath with 4. How does Black answer White 6 ? ENDCOM B 1 N16 USER CORRECT ANSWER ENDUSER COM Correct Answer. Although his position looks precarious, Black has nothing to fear. Black ataris with 1 ... ENDCOM W 2 M15 B 3 L14 COM ... and extends to 3. Before White does anything else, she must resolve the problem of the ladder. ENDCOM W 4 N15 COM White must escape the ladder by playing 4. ENDCOM B 5 K17 W 6 L18 B 7 J17 MARK 5@K17 COM Now Black forces with 5 and 7, ... ENDCOM W 8 M18 MARK 6@L18 COM ... forcing White to play 6 and 8. ENDCOM B 9 G16 COM Finally, Black plays 9 for an excellent result. <= ENDCOM EVENT BOARDSIZE 19 SETUP W J17 N18 O17 N16 P16 SETUP B D16 G17 K16 M17 P17 Q17 R16 R14 COM Problem 33. White to play. How does White answer Black 1 ? ENDCOM W 1 K17 USER CORRECT ANSWER ENDUSER COM Correct Answer. White 1 is the only move. ENDCOM VAR W 1 J16 COM Failure. Pushing up with 1 ... ENDCOM B 2 K17 W 3 K15 B 4 J18 W 5 H18 B 6 K18 W 7 H17 B 8 L15 COM ... results in the moves to 8. The white stones on the right now come under attack. <= ENDCOM ENDVAR B 2 L17 W 3 L18 B 4 M18 W 5 M19 COM Up to 5, White has linked up with her allies on the right. ENDCOM B 6 K18 W 7 L19 B 8 J16 W 9 J18 B 10 H17 MARK A@M15 COM Later, White can aim at A. <= ENDCOM EVENT BOARDSIZE 19 SETUP W K17 M16 O17 Q18 SETUP B D16 G17 M17 R17 Q16 Q14 MARK 1@M17 2@M16 COM Problem 34. Black to play. If White responds to Black's invasion by attaching on top with 2, how should Black answer ? ENDCOM B 1 N17 MARK \t@M16 USER CORRECT ANSWER ENDUSER COM Correct Answer. Against the marked white stone Black should play 1 ... ENDCOM W 2 N16 B 3 O18 MARK B@P18 A@O16 COM ... and 3, and the situation is similar to the answer in Problem 31. Black can link up by playing at A or B. <= ENDCOM EVENT BOARDSIZE 19 SETUP W F17 K16 O17 M16 SETUP B D16 D14 Q16 Q14 M17 L17 MARK 2@M16 3@L17 1@M17 COM Problem 35. White to play. Black 3 is straightforward and avoids complications, but it is a bit lukewarm. How should White respond ? ENDCOM W 1 L16 USER CORRECT ANSWER ENDUSER COM Correct Answer. White should play 1 ... ENDCOM B 2 N17 W 3 N16 COM ... and 3. ENDCOM B 4 P17 MARK 2@N17 COM Black is still able to link up his stones with 2 and 4, but ... ENDCOM W 5 O18 B 6 O16 W 7 P18 MARK 5@O18 COM White keeps the pressure up with 5 and 7, ... ENDCOM B 8 Q18 W 9 R17 B 10 Q17 W 11 O15 B 12 P16 W 13 K17 MARK 9@R17 11@O15 COM ... enabling her to play the forcing moves of 9, 11, and 13. The result for Black is not so good as in Problem 32. <= ENDCOM B 14 N18 EVENT BOARDSIZE 19 SETUP W J17 N16 O17 P16 N18 SETUP B D16 G17 M17 K18 P17 Q17 R16 R14 MARK 1@K18 COM Problem 36. White to play. How does White respond to Black 1 ? ENDCOM W 1 L16 USER CORRECT ANSWER ENDUSER COM Correct Answer. White 1 is the only move. <= ENDCOM VAR W 1 J18 COM Failure. Preventing Black from linking up with 1 fails. ENDCOM B 2 K17 W 3 J16 B 4 L15 MARK 2@K17 COM Black plays 2 and 4 and the white stones on both sides come under siege. <= ENDCOM ENDVAR VAR W 1 K17 COM Failure. ENDCOM B 2 L17 W 3 J18 B 4 L15 COM <= ENDCOM ENDVAR EVENT BOARDSIZE 19 SETUP W L17 P16 Q17 R17 SETUP B D17 C15 J17 S17 R16 S15 Q14 MARK \t@Q14 \t@J17 COM Problem 37. Black to play. Since Black has played the two marked stones, he dominates the top of the board. From this strength, where should he invade ? ENDCOM B 1 N17 USER CORRECT ANSWER ENDUSER COM Correct Answer. Jumping into the middle of White's formation with 1 is the vital point. ENDCOM W 2 N16 COM If White attaches with 2, ... ENDCOM B 3 M17 W 4 M16 B 5 L18 W 6 L16 VAR W 6 O17 COM Variation. If White settles herself with 6, ... ENDCOM B 7 L16 W 8 L15 B 9 K16 MARK 7@L16 COM ... Black is more than happy to play 7 and 9. <= ENDCOM ENDVAR B 7 K17 COM ... Black links up his stones with the moves to 7. <= ENDCOM EVENT BOARDSIZE 19 SETUP W C14 H17 O17 SETUP B D16 F16 Q16 Q14 R10 COM Problem 38. Black to play. Here is a position that often occurs in handicap games. Where should Black invade ? ENDCOM B 1 L16 USER CORRECT ANSWER ENDUSER COM Correct Answer. The high invasion of Black 1 is correct. <= ENDCOM VAR B 1 L17 COM Dangerous. Invading deeply at 1 is also possible, but this could be risky because White would have many chances to seize the initiative. <= ENDCOM ENDVAR EVENT BOARDSIZE 19 SETUP W J17 N16 O17 N18 P16 L16 SETUP B D16 G17 P17 Q17 R16 R14 M17 K18 MARK \t@L16 COM Problem 39. Black to play. In response to the marked white stone, Black has a tesuji that he must play. Where is it ? ENDCOM B 1 K16 USER CORRECT ANSWER ENDUSER COM Correct Answer. Attaching with 1 is Black's tesuji. <= ENDCOM VAR B 1 J18 COM Failure. Simply crawling with 1 ... ENDCOM W 2 L17 COM ... lets White play 2, giving her thickness on the outside. <= ENDCOM ENDVAR EVENT BOARDSIZE 19 SETUP W L17 M16 P16 Q17 R17 SETUP B D17 C15 J17 N17 S17 R16 S15 Q14 MARK 2@M16 1@N17 COM Problem 40. Black to play. White responds Black's invasion with the diagonal move of 2. How should Black respond ? ENDCOM B 1 N16 USER CORRECT ANSWER ENDUSER COM Correct Answer. Black should push up with 1, ... ENDCOM W 2 N15 B 3 L18 COM ... then attach with 3. ENDCOM W 4 K18 B 5 M18 W 6 K17 COM After White 6, ... ENDCOM B 7 J18 W 8 O15 B 9 K19 MARK 7@J18 COM ... Black links up his stones with 7 and 9, ... ENDCOM W 10 K15 MARK 8@O15 COM ... while White makes thickness in the center with 8 and 10. <= ENDCOM EVENT BOARDSIZE 19 SETUP W C14 H17 O17 SETUP B D16 F16 L17 Q16 Q14 R10 MARK 1@L17 COM Problem 41. White to play. Black has invaded deeply with 1. How should White play ? ENDCOM W 1 H15 USER CORRECT ANSWER ENDUSER COM Correct Answer. White should first exchange 1 ... ENDCOM B 2 F14 COM ... for Black 2, ... ENDCOM W 3 Q17 COM ... then attach with 3 ... ENDCOM B 4 R17 W 5 R18 COM ... and 5, ... ENDCOM B 6 S18 COM ... hoping to lure Black in to playing 6. ENDCOM W 7 L15 COM White then caps the black stone with 7. <= ENDCOM B 8 M16 COM Running away with 8 is natural, but ... ENDCOM W 9 M15 B 10 N16 W 11 R16 COM ... then White switches to the corner and ... ENDCOM B 12 S17 W 13 Q15 B 14 P16 W 15 O16 MARK 11@R16 13@Q15 COM ... forces with 11, 13, and 15. ENDCOM B 16 P15 W 17 O15 COM After White 17, the black stones in the center are trapped. <= ENDCOM EVENT BOARDSIZE 19 SETUP W J17 N16 O17 N18 P16 L16 SETUP B D16 G17 P17 Q17 R16 R14 K18 K16 M17 MARK 3@K16 2@L16 1@K18 COM Problem 42. White to play. How does White respond to Black 3 ? ENDCOM W 1 K17 USER CORRECT ANSWER ENDUSER COM Correct Answer. White should push through with 1 and ... ENDCOM VAR W 1 Q15 USER CORRECT ANSWER ENDUSER COM Correct Answer. White can avoid complications by first exchanging 1 ... ENDCOM B 2 R15 COM ... for 2 ... ENDCOM W 3 K17 COM ... before playing 3. ENDCOM B 4 L17 W 5 L15 B 6 J18 W 7 H17 B 8 H18 W 9 J15 MARK A@M16 COM This defends against Black pushing through at A after White 9. White gets nice thickness with the joseki to 9. <= ENDCOM ENDVAR B 2 L17 W 3 M16 B 4 J18 W 5 H17 B 6 H18 W 7 K15 MARK A@J16 COM ... play the moves to 7. This is joseki. Black can still play A, leading to a complicated fight. <= ENDCOM EVENT BOARDSIZE 19 SETUP W K19 K18 K17 L17 M16 N15 P16 Q17 R17 SETUP B D17 C15 J17 J18 L18 M18 N17 N16 S17 R16 S15 Q14 MARK 2@K19 1@J18 COM Problem 43. Black to play. White stops Black from linking up by descending to 2. What should Black do ? ENDCOM B 1 O15 USER CORRECT ANSWER ENDUSER COM Correct Answer. Black should play 1, isolating the three white stones on the right. ENDCOM W 2 O16 COM If White cuts with 2, ... ENDCOM B 3 O18 COM ... Black makes shape with 3. ENDCOM W 4 M15 COM White must defend with 4, but, ... ENDCOM B 5 P15 COM ... after 5, the four white stones on the right are dead. <= ENDCOM EVENT BOARDSIZE 19 SETUP W C14 H15 H17 O17 Q17 R18 SETUP B D16 F16 F14 L17 R17 Q16 Q14 R10 MARK 1@R18 COM Problem 44. Black to play. How should Black answer White 1 ? ENDCOM B 1 P17 USER CORRECT ANSWER ENDUSER COM Correct Answer. Black must not passively play as in Problem 41. Instead he should take the initiative by playing 1. ENDCOM W 2 Q18 B 3 P16 COM If Black wants thickness, he can play the joseki from 3 to ... ENDCOM VAR B 3 P18 COM Variation. If Black wants profit in the corner, he will block at 3. ENDCOM W 4 P16 B 5 O18 W 6 O16 B 7 N18 W 8 Q15 B 9 R16 W 10 R15 B 11 S15 W 12 R14 B 13 S14 W 14 R13 B 15 S18 COM The moves to 15 are also joseki. Black can make a deep invasion if he knows these josekis. <= ENDCOM ENDVAR W 4 P18 B 5 O16 W 6 N17 B 7 M15 COM 7. <= ENDCOM EVENT BOARDSIZE 19 SETUP W F17 L16 O16 O17 SETUP B D14 D16 P17 Q16 Q14 COM Problem 45. Black to play. There are so many places where Black can invade. Where do you think is the best point ? ENDCOM B 1 J16 USER CORRECT ANSWER ENDUSER COM Correct Answer. Black should play near White's strong side with 1. This is the correct invasion point. ENDCOM VAR B 1 H16 COM Failure. Even though it is high, playing 1 one line to the left is dubious. ENDCOM W 2 H17 B 3 J17 W 4 J16 MARK 2@H17 COM White 2 and 4 hit the mark, Black cannot get a good result. <= ENDCOM ENDVAR W 2 F15 COM If White jumps to 2, ... ENDCOM B 3 J14 COM ... Black is also happy to jump to 3. Black has split White into 2 groups. <= ENDCOM EVENT BOARDSIZE 19 SETUP W H17 M16 R16 Q14 R10 SETUP B D17 C15 O16 P17 R18 COM Problem 46. Black to play. White's stones at the top are nicely balanced, but she is still vulnerable to an invasion. Where should Black invade ? ENDCOM B 1 K17 USER CORRECT ANSWER ENDUSER COM Correct Answer. Black 1, in the middle of the three-space extension, is the vital point. ENDCOM W 2 K16 COM White 2 is the best response, but ... ENDCOM B 3 L17 W 4 L16 B 5 M17 W 6 J17 B 7 N16 COM ... Black links up with the moves to 7. <= ENDCOM EVENT BOARDSIZE 19 SETUP W C14 H17 H15 L14 O17 SETUP B D16 F16 F14 L16 Q16 Q14 R10 MARK 1@L14 COM Problem 47. Black to play. White caps the black stone in the center with 1. How should Black respond ? ENDCOM B 1 N16 USER CORRECT ANSWER ENDUSER COM Correct Answer. By playing 1, Black turns the tables on White. ENDCOM W 2 O16 B 3 N15 COM White must save her stones on the right, while Black is in no danger. <= ENDCOM EVENT BOARDSIZE 19 SETUP W F17 J17 L16 O16 O17 SETUP B D16 D14 J16 P17 Q16 Q14 MARK 2@J17 1@J16 COM Problem 48. Black to play. White attaches at 2, aiming to make sabaki. How should Black respond ? ENDCOM B 1 H17 USER CORRECT ANSWER ENDUSER COM Correct Answer. Black should block at 1. ENDCOM W 2 H16 COM White then crosscuts with 2, the usual way of making sabaki. But, ... ENDCOM B 3 G16 COM ... Black counters White's plan by playing atari with 3 ... ENDCOM W 4 H15 B 5 J18 MARK \t@J16 COM ... and 5, discarding his marked stone. ENDCOM W 6 K17 B 7 G17 MARK A@C17 COM Black is thick on the left, it will be hard for White to invade the corner at A. <= ENDCOM EVENT BOARDSIZE 19 SETUP W H17 J17 K16 L16 M16 R16 Q14 R10 SETUP B D17 C15 K17 L17 M17 O16 P17 R18 MARK A@N16 COM Problem 49. White to play. Black has neglected to play at A. What should White do ? ENDCOM W 1 N17 MARK A@N16 USER CORRECT ANSWER ENDUSER COM Correct Answer. Neglecting to play at A is a mistake, since White will hane with 1. ENDCOM B 2 N18 COM Black has no choice but to submissively link up with 2 ... ENDCOM W 3 N16 B 4 O18 COM ... and 4, ... ENDCOM W 5 O15 COM ... after which White becomes thick in the center when she plays 5. <= ENDCOM EVENT BOARDSIZE 19 SETUP W C14 H17 H15 O17 O15 R12 SETUP B D16 F16 F14 L16 Q16 Q14 MARK A@L17 \t@R12 1@O15 COM Problem 50. Black to play. This time White has the marked stone in place on the right side. How should Black answer White 1 now ? ENDCOM B 1 P13 USER CORRECT ANSWER ENDUSER COM Correct Answer. Black must move out into the center with 1. ENDCOM W 2 L14 COM If White caps with 2, ... ENDCOM B 3 N16 COM ... Black can easily break out into the center with 3, ... ENDCOM W 4 O16 COM ... White 4, ... ENDCOM B 5 M14 COM ... Black 5. <= ENDCOM EVENT BOARDSIZE 19 SETUP W F17 L16 O16 O17 SETUP B D16 D14 H17 P17 Q16 Q14 MARK 1@H17 COM Problem 51. White to play. Black makes a deep invasion with 1. What should White do ? ENDCOM W 1 H15 MARK \t@H17 USER CORRECT ANSWER ENDUSER COM Correct Answer. Against the marked black stone, White will cap at 1. ENDCOM B 2 G16 COM After Black runs away with 2, ... ENDCOM W 3 D17 COM ... White attaches at 3 and can easily make a living group in the corner. <= ENDCOM EVENT BOARDSIZE 19 SETUP W H17 K16 M16 R16 Q14 R10 SETUP B D17 C15 K17 L16 O16 P17 R18 MARK 1@L16 COM Problem 52. White to play. Although it looks like a tesuji, Black 1 is a dubious move. How should White respond ? ENDCOM W 1 L17 USER CORRECT ANSWER ENDUSER COM Correct Answer. White should atari with 1 and ... ENDCOM VAR W 1 L15 B 2 L17 W 3 J16 B 4 M17 ENDVAR B 2 L15 W 3 K18 B 4 M17 W 5 J17 B 6 L18 W 7 K17 VAR W 7 M18 MARK @@K17 COM Instead of connecting at @, White could opt for a ko by playing at 7. This could be dangerous for Black. <= ENDCOM ENDVAR B 8 M18 W 9 F17 MARK B@L14 A@M15 COM ... play the moves to 9 (later White can start a fight with A, Black B). <= ENDCOM EVENT BOARDSIZE 19 SETUP W D16 C17 F16 L17 SETUP B N17 Q16 R15 B16 C14 C11 COM Problem 53. White to play. Black's three stones on the right are a bit thin. Where is the vital point to invade ? ENDCOM W 1 P17 USER CORRECT ANSWER ENDUSER COM Correct Answer. White 1 is the vital point. ENDCOM B 2 Q17 COM After Black answers with 2, ... ENDCOM W 3 Q18 VAR W 3 P16 MARK 2@Q17 COM Failure. Answering 2 with 3 is bad. ENDCOM B 4 P15 COM Black forces with 4, ... ENDCOM W 5 O16 B 6 P18 W 7 O18 B 8 Q18 MARK 6@P18 COM ... 6, and 8. ENDCOM W 9 O17 COM After 9, White is left with bad shape. <= ENDCOM ENDVAR B 4 P16 W 5 O17 B 6 O16 W 7 N18 B 8 R18 W 9 P18 COM ... White will link up with the moves to 9. ENDCOM B 10 N16 COM <= ENDCOM EVENT BOARDSIZE 19 SETUP W K17 O17 O16 P16 SETUP B D16 H17 P17 Q17 R16 R14 COM Problem 54. Black to play. Where should Black invade White's formation at the top ? ENDCOM B 1 M17 USER CORRECT ANSWER ENDUSER COM Correct Answer. Black 1 is the best move. ENDCOM W 2 M16 COM If White attaches at 2, ... ENDCOM VAR W 2 L16 COM Failure. The diagonal move of 2 is not good. ENDCOM B 3 M16 COM Black pushes up with 3, ... ENDCOM W 4 M15 B 5 M18 MARK B@O18 A@K18 COM ... then descends to 5, enabling him to link up with A or B. White's stones are thin and vulnerable. <= ENDCOM ENDVAR B 3 M18 COM ... Black descends to 3 and ... ENDCOM W 4 L16 B 5 O18 MARK A@K18 COM ... he can link either at 5 or at A. White is satisfied with her thickness. <= ENDCOM EVENT BOARDSIZE 19 SETUP W M16 R14 Q10 R6 B16 C14 C11 SETUP B C17 D16 F16 K16 O16 Q16 Q4 O4 K4 D4 MARK 1@M16 COM Problem 55. Black to play. The invasion of White 1 often occurs in handicap games. How should Black respond ? ENDCOM B 1 L15 USER CORRECT ANSWER ENDUSER COM Correct Answer. The diagonal move of Black 1 is the strongest response. ENDCOM VAR B 1 N15 MARK A@L15 USER CORRECT ANSWER ENDUSER COM Correct Answer. Playing the diagonal move of Black 2 from the right is also correct. It often transposes into the position of the Correct Answer starting with Black A. <= ENDCOM ENDVAR VAR B 1 K14 USER CORRECT ANSWER ENDUSER COM Correct Answer. Jumping to 2 is also possible. ENDCOM W 2 M14 COM After White 2, ... ENDCOM B 3 P13 COM ... Black jumps to 3, attacking the white stones on both the right and left. If you are good at fighting, you can play this way. <= ENDCOM ENDVAR VAR B 1 K17 COM Failure. Black 1 is overly defensive. ENDCOM W 2 M14 COM After White jumps to 2, ... ENDCOM VAR W 2 M18 MARK 1@K17 COM Variation. White might respond to Black 1 by jumping to 2. ENDCOM B 3 N15 COM In this case, Black will certainly play at 3. <= ENDCOM ENDVAR B 3 M17 COM ... Black must defend again at 3. Black has enormous power at the top, so he must not play so submissively. <= ENDCOM ENDVAR VAR B 1 M15 COM Failure. Attaching at 1 is not recommended. ENDCOM W 2 L15 B 3 L16 W 4 N15 B 5 M17 W 6 M14 B 7 N17 COM Black can take territory at the top, but White's ponnuki gives her the strategic advantage. <= ENDCOM ENDVAR VAR B 1 M17 COM Failure. Attaching underneath with Black 1 is also bad. ENDCOM W 2 L17 B 3 L16 VAR B 3 N17 MARK 1@M17 COM Very bad. Drawing back with 3 after attaching at 1 is very bad. ENDCOM W 4 L16 MARK \t@K16 A@R17 COM White connects at 4 and the marked stone has lost much of its value. White also has the option of invading at A. <= ENDCOM ENDVAR W 4 N17 B 5 M15 W 6 M18 B 7 N16 W 8 K17 COM White lives at the top with the moves to 8. Black has no territory and his thickness is not very effective. <= ENDCOM ENDVAR W 2 M15 COM Black confines White to the side with the moves from 2 ... ENDCOM B 3 M14 W 4 N14 B 5 N15 COM ... to 5. This is joseki. ENDCOM VAR B 5 M13 MARK B@N15 4@N14 COM Failure. When White hanes with 4, Black must cut with B (5 in the Correct Answer). Playing 5 as here is timid. ENDCOM W 6 O15 COM White gets a good result when she connects with 6. <= ENDCOM ENDVAR W 6 M18 MARK B@P17 A@J17 COM Continuation 1. White jumps down to 6: she aims at either A or B. ENDCOM B 7 K18 COM Black 8 is best, taking the larger territory on the left. ENDCOM VAR B 7 O18 COM Variation. Attacking from the right with Black 7 is also possible. ENDCOM W 8 J17 COM White jumps to 8 and ... ENDCOM B 9 K17 W 10 K18 B 11 L17 W 12 L18 B 13 M17 MARK 7@O18 A@K18 11@L17 COM ... Black captures two stones with 11 and 13. Black's result is inferior to that beginning with Black A instead of 7. <= ENDCOM ENDVAR W 8 P17 COM With 8, White starts making two eyes at the top. ENDCOM B 9 P16 W 10 N16 B 11 O15 W 12 O17 B 13 Q17 W 14 Q18 B 15 R18 W 16 P19 COM The moves to 16 are joseki and White's group at the top is alive. Black is satisfied with his territory at the top left and his thickness in the center. <= ENDCOM EVENT BOARDSIZE 19 SETUP W M17 R14 Q10 R6 C14 B16 C11 SETUP B C17 D16 F16 K16 O16 Q16 Q4 O4 K4 D4 MARK 1@M17 COM Problem 56. Black to play. The deep invasion of 1 is another move White has in her arsenal. How does Black reply in this case ? ENDCOM B 1 M16 USER CORRECT ANSWER ENDUSER COM Correct Answer. Attaching with Black 1 is the strongest move. White is now forced to make life on the side. ENDCOM VAR B 1 O17 COM Failure. Defending with Black 1 is bad. When White makes a deep invasion, your first instinct should be to confine her to the side. ENDCOM W 2 M15 COM <= ENDCOM VAR W 2 K17 MARK @@M15 COM Instead of @, White could attach at 2. ENDCOM B 3 J17 COM Black plays 3 and ... ENDCOM W 4 J16 COM ... White cuts at 4. <= ENDCOM ENDVAR ENDVAR VAR B 1 N17 MARK A@L17 COM Failure. Attaching with 1 (or A) is even worse. ENDCOM W 2 M16 B 3 O14 W 4 M14 MARK A@P17 COM White is out into the center and still threatens a move at A. <= ENDCOM ENDVAR VAR B 1 K17 USER CORRECT ANSWER ENDUSER COM Correct Answer. If you are going to defend, Black 1 is the only way. ENDCOM W 2 M15 COM After White 2, ... ENDCOM B 3 P13 COM ... Black jumps to 3, attacking White on both the right and the left. <= ENDCOM ENDVAR W 2 N17 B 3 N16 W 4 L17 B 5 K17 W 6 Q18 VAR W 6 L16 COM White could push through with 6 ... ENDCOM B 7 L15 W 8 K18 B 9 J18 W 10 L19 B 11 K15 W 12 P18 COM ... and live with the moves to 12. This is also joseki. <= ENDCOM ENDVAR B 7 L16 W 8 O17 COM The moves to 8 are joseki. Black gets territory on the left and thickness in the center. <= ENDCOM EVENT BOARDSIZE 19 SETUP W B16 C14 C11 M16 M15 N15 R14 Q10 SETUP B C17 D16 F16 K16 L15 M14 O16 Q16 MARK A@N14 1@N15 COM Problem 57. Black to play. White seems to be afraid to play 1 at A ( White 5 in the Correct Answer to Problem 55), but White 1 here is a bad move. How does Black take advantage of this mistake ? ENDCOM B 1 Q14 USER CORRECT ANSWER ENDUSER COM Correct Answer. Black shifts the attack to the right with 1 ... ENDCOM W 2 Q13 B 3 P14 COM ... and 3. ENDCOM W 4 R15 MARK 2@Q13 COM If White 2 and 4, ... ENDCOM VAR W 4 N14 COM Variation. If White might turn at 5, ... ENDCOM B 5 R13 COM ... Black cuts at 5, seizing the initiative on the right side. <= ENDCOM ENDVAR B 5 N14 COM ... Black plays 5. The white stones at the top are almost dead. <= ENDCOM EVENT BOARDSIZE 19 SETUP W B16 C14 C11 J16 K17 M16 R14 Q10 SETUP B C17 D16 F16 K16 J17 N15 O16 Q16 MARK 5@J16 4@J17 3@K17 2@N15 1@M16 COM Problem 58. Black to play. Black 2 gives White the chance to attach and cut with 3 and 5 on the left. With good play, however, Black can come out of this position with an advantage. How should Black play ? ENDCOM B 1 L17 USER CORRECT ANSWER ENDUSER COM Correct Answer. Black should atari with 1 ... ENDCOM VAR B 1 K18 USER CORRECT ANSWER ENDUSER COM Correct Answer. Black could also play 1 ... ENDCOM W 2 L17 B 3 H17 COM ... and 3. ENDCOM W 4 K15 B 5 H16 W 6 J15 B 7 L18 W 8 M18 B 9 N17 W 10 M17 B 11 H15 COM After 11, White's group is still not alive , so Black can make further gains by attacking it. <= ENDCOM ENDVAR W 2 K18 B 3 H17 COM ... and extend to 3. ENDCOM W 4 L16 COM After 4, ... ENDCOM B 5 K15 W 6 M17 B 7 L14 COM ... Black confines White to the side with 7. ENDCOM VAR B 7 J18 MARK @@L14 COM Instead of 7 at @, Black could play here. ENDCOM W 8 L18 B 9 N18 COM <= ENDCOM ENDVAR W 8 O18 COM White lives with 8. <= ENDCOM EVENT BOARDSIZE 19 SETUP W R14 Q10 B16 C14 C11 M17 L16 SETUP B C17 D16 F16 K16 O16 Q16 M16 MARK 1@L16 COM Problem 59. Black to play. White wedges in with 1. How should Black respond ? ENDCOM B 1 L15 USER CORRECT ANSWER ENDUSER COM Correct Answer. Black should atari from above with 1. ENDCOM VAR B 1 L17 COM Failure. Playing atari from underneath with 1 is not good. ENDCOM W 2 L15 B 3 N17 W 4 K17 B 5 M18 W 6 L18 B 7 M17 W 8 J16 COM After White 8, the three black stones on the left will come under attack. <= ENDCOM ENDVAR W 2 L17 B 3 K17 W 4 N16 B 5 M15 W 6 O17 B 7 N15 W 8 N17 B 9 P17 W 10 O15 B 11 P16 W 12 K18 B 13 J18 W 14 L19 B 15 K15 W 16 P18 B 17 Q18 W 18 P19 COM White lives with the moves to 18, but ... ENDCOM B 19 O14 COM ... Black's thickness in the center after 19 is overwhelming. <= ENDCOM EVENT BOARDSIZE 19 SETUP W B16 C14 C12 M15 M16 N15 N14 R15 R14 Q13 Q10 SETUP B C17 D16 F16 K16 L15 M14 O16 Q16 P14 Q14 R13 MARK 1@R15 COM Problem 60. Black to play. How does Black answer White 1 ? ENDCOM B 1 R16 USER CORRECT ANSWER ENDUSER COM Correct Answer. Black should calmly block with 1 and, ... ENDCOM W 2 R12 COM ... when White ataris with 2, ... ENDCOM B 3 S13 COM ... descend to 3. ENDCOM W 4 S12 COM After White 4, ... ENDCOM B 5 Q12 W 6 P13 B 7 O13 MARK 5@Q12 COM ... Black ataris with 5 and 7, ... ENDCOM W 8 P12 B 9 N13 COM ... then plays 9, confining White to the top. <= ENDCOM EVENT BOARDSIZE 19 SETUP W J16 K17 M16 R14 Q10 SETUP B D16 D14 D10 J17 K16 N15 O16 Q16 COM Problem 61. Black to play. A ladder towards the left would be favourable for Black. What is his strongest play ? ENDCOM B 1 K15 USER CORRECT ANSWER ENDUSER COM Correct Answer. Since the ladder is favourable for Black, 1 is a powerful move. ENDCOM W 2 H17 B 3 J18 W 4 H18 B 5 K18 W 6 L17 B 7 L18 W 8 M18 B 9 N17 COM With the moves to 9, White's stones at the top are in trouble. Next, ... ENDCOM W 10 M17 B 11 H16 COM ... Black ataris with 11, but, ... ENDCOM W 12 J15 B 13 J14 W 14 H15 B 15 G16 W 16 H14 B 17 G17 COM ... after the moves to 17, ... ENDCOM W 18 M15 B 19 K14 W 20 M14 MARK 18@M15 COM ... White must escape into the center with 18 and 20. ENDCOM B 21 H13 COM After Black 21 the top left quarter of the board is dominated by Black. <= ENDCOM EVENT BOARDSIZE 19 SETUP W C14 C11 B16 M17 N16 R14 Q10 SETUP B C17 D16 F16 K16 M16 O16 Q16 MARK 1@N16 COM Problem 62. Black to play. This time White wedges in on the right side. This is a bad move. How does Black respond ? ENDCOM B 1 N17 USER CORRECT ANSWER ENDUSER COM Correct Answer. This time Black must atari from below with 1. ENDCOM W 2 N15 B 3 M15 COM The moves from 3 ... ENDCOM W 4 O17 B 5 N18 W 6 P17 B 7 N14 W 8 O15 B 9 P16 W 10 M18 B 11 O14 W 12 P15 COM ... to 12 are now inevitable. ENDCOM B 13 Q14 COM Black next plays 13 and ... ENDCOM W 14 N19 B 15 P14 W 16 O18 MARK 14@N19 COM ... White must capture with 14 and 16. ENDCOM B 17 N17 W 18 N18 B 19 Q15 COM After Black 19, White can live at the top, but Black's thickness in the center is overwhelming. <= ENDCOM EVENT BOARDSIZE 19 SETUP W B16 C14 C11 R14 Q10 K18 SETUP B C17 D16 F16 K16 O16 Q16 MARK 1@K18 COM Problem 63. Black to play. White invades at 1. Although on the second line, it is a vital point of this formation. How should Black respond ? ENDCOM B 1 K17 USER CORRECT ANSWER ENDUSER COM Correct Answer. Black 1 is the vital point. ENDCOM VAR B 1 L17 COM Failure. The diagonal move of Black 1 is lukewarm. ENDCOM W 2 L18 COM White first pushes into Black's side with 2, ... ENDCOM B 3 M17 W 4 H17 COM ... then jumps to 4. ENDCOM B 5 H16 COM After Black attaches with 5, ... ENDCOM W 6 G17 B 7 G16 W 8 E18 MARK 8@G17 COM ... White easily lives with 6 and 8. <= ENDCOM ENDVAR W 2 H17 COM If White jumps to 2, ... ENDCOM VAR W 2 J18 COM Variation. If White extends to 2, ... ENDCOM B 3 L18 COM ... Black still blocks at 3. ENDCOM W 4 H17 COM After the exchange of White 4 ... ENDCOM B 5 H16 COM ...for Black 5, White can live, but this time Black gets both territory at the top right and thickness in the center. <= ENDCOM ENDVAR B 3 L18 COM ... Black will block off the territory at the top right with 3. ENDCOM W 4 H15 COM White then escapes into the center with 4, ... ENDCOM B 5 F14 COM ... and Black follows suit with 5. Black gets territory and White is still under attack. <= ENDCOM EVENT BOARDSIZE 19 SETUP W B16 C14 C11 R14 Q10 O18 SETUP B D16 C17 F16 K16 O16 Q16 MARK 1@O18 COM Problem 64. Black to play. This time White invades at 1, a trick move where Black can easily go wrong. What is Black's strongest and safest response ? ENDCOM B 1 R17 USER CORRECT ANSWER ENDUSER COM Correct Answer. Black 1 on the 3-3 point is a safe and steady move. ENDCOM VAR B 1 O17 COM Failure. This time bumping into White with Black 1 is not a good move. ENDCOM W 2 R17 COM White can jump to 2 and ... ENDCOM B 3 R16 W 4 P18 B 5 N18 W 6 S17 MARK 4@P18 COM ... skilfully live with 4 and 6. <= ENDCOM ENDVAR W 2 M17 COM In order to get life, White must jump to 2, but ... ENDCOM B 3 M16 COM ... Black confines her to the side with 3. Next, ... ENDCOM W 4 L17 B 5 K17 W 6 L16 B 7 L15 W 8 N16 B 9 N15 W 10 M15 COM ... White tries to break out into the center with the moves to 10, but ... ENDCOM B 11 M14 COM ... Black keeps White confined to the top of the board with 11. White will have a hard time living. <= ENDCOM EVENT BOARDSIZE 19 SETUP W B16 C14 C11 R14 Q10 N17 R16 Q17 Q18 SETUP B D16 C17 F16 K16 O16 Q16 N16 R17 P17 MARK 7@Q18 6@P17 5@Q17 4@R17 3@R16 2@N16 1@N17 COM Problem 65. Black to play. White 1 and 3 are also trick moves. Black 4 and 6 are natural responses, but what does Black do after White 7 ? ENDCOM B 1 R18 USER CORRECT ANSWER ENDUSER COM Correct Answer. Black should force White from the right with 1, ... ENDCOM VAR B 1 P18 COM Failure. Forcing on the other side with 1 is not good. ENDCOM W 2 Q15 B 3 P16 W 4 R18 MARK 2@Q15 COM White gets the corner with 2 and 4, and Black's stones at the top are overconcentrated. <= ENDCOM ENDVAR W 2 P18 B 3 O18 COM ... then play 3, ... ENDCOM W 4 O17 COM ... inducing White to atari with 4. ENDCOM B 5 P16 COM After Black connects with 5, ... ENDCOM W 6 N18 B 7 R15 COM ... he can play 7, breaking into White's moyo on the right. White's stones at the top are still in danger. <= ENDCOM EVENT BOARDSIZE 19 SETUP W C12 C16 E17 H17 R10 Q18 SETUP B C10 K17 Q17 R15 P17 MARK 2@P17 1@Q18 COM Problem 66. White to play. White has attacked the small-knight enclosure by attaching at 1. How should White follow up his invasion after Black extends to 2 ? ENDCOM W 1 R17 USER CORRECT ANSWER ENDUSER COM Correct Answer. White easily lives in the corner ... ENDCOM VAR W 1 P18 USER CORRECT ANSWER ENDUSER COM Correct Answer. Living in the corner is small, so White might play 1 ... ENDCOM B 2 R18 W 3 O17 COM ... and 3. ENDCOM B 4 M17 COM If Black attacks with 4, ... ENDCOM W 5 O15 MARK C@R17 D@R16 B@R14 A@Q15 COM ... White jumps to 5, aiming to make sabaki by attaching at A. If then Black B, White plays C, if Black D, White answers with B. <= ENDCOM ENDVAR B 2 R16 W 3 S17 COM ... with 3 ... ENDCOM B 4 P18 W 5 R19 COM ... and 5. However, the corner territory is small and White ends in gote, so the timing in playing these moves is crucial. <= ENDCOM EVENT BOARDSIZE 19 SETUP W N17 Q17 R14 B16 C14 C11 SETUP B C17 D16 F16 K17 COM Problem 67. Black to play. Black wants to invade at the top right. Where should he play ? ENDCOM B 1 O16 USER CORRECT ANSWER ENDUSER COM Correct Answer. Black first makes a shoulder hit at 1 and, ... ENDCOM W 2 O17 COM ... after White defends at 2, ... ENDCOM B 3 R16 COM ... invades the corner with 3. ENDCOM W 4 Q16 B 5 R15 W 6 Q15 MARK 4@Q16 COM If White 4 and 6, ... ENDCOM B 7 S14 W 8 R13 B 9 S13 W 10 R12 B 11 R17 COM ... Black lives in the corner with the moves to 11, his invasion is a success. <= ENDCOM EVENT BOARDSIZE 19 SETUP W D18 F17 J17 R10 SETUP B C17 D16 D14 C10 N17 Q16 COM Problem 68. White to play. Black has stones on both the left and the right. Where should White invade ? ENDCOM W 1 R17 USER CORRECT ANSWER ENDUSER COM Correct Answer. White 1 is good timing. ENDCOM B 2 R16 MARK \t@R10 COM If Black 2, his thickness facing the bottom is negated by White's marked stone. ENDCOM VAR B 2 Q17 COM Variation. There are times when Black might want to block with 2, but ... ENDCOM W 3 R16 COM ... the black stones are left with a heavy shape. <= ENDCOM ENDVAR W 3 Q17 MARK C@P16 B@P17 A@S17 COM Next, Black can play A, B, or C. <= ENDCOM EVENT BOARDSIZE 19 SETUP W C16 E17 C12 H17 R10 Q18 SETUP B C10 K17 Q17 R15 Q16 MARK 2@Q16 1@Q18 COM Problem 69. White to play. This time Black pulls back with 2 in answer to 1. What should White do ? ENDCOM W 1 O17 USER CORRECT ANSWER ENDUSER COM Correct Answer. White should lightly jump to 1 and, ... ENDCOM VAR W 1 R18 COM Failure. White must not play 1 because ... ENDCOM B 2 P18 COM ... Black 2 will kill her. <= ENDCOM ENDVAR VAR W 1 P18 COM Failure. White 1 is a heavy move. ENDCOM B 2 R18 W 3 M17 COM After 3, ... ENDCOM B 4 O17 COM ... Black 4 ... ENDCOM W 5 O18 B 6 N17 W 7 N18 B 8 L18 COM ... to 8 will leave White with only one eye. ENDCOM W 9 M18 B 10 K15 COM With Black 10, White is under attack and she must now find her second eye in the center. <= ENDCOM ENDVAR B 2 P18 COM ... if Black plays 2, ... ENDCOM W 3 M17 MARK A@P17 COM ... jump again to 3. White can later threaten Black with A. <= ENDCOM EVENT BOARDSIZE 19 SETUP W Q17 O17 N17 R14 Q15 B16 C14 C11 SETUP B C17 D16 F16 K17 O16 R16 MARK 1@Q15 COM Problem 70. Black to play. If White defends with 1, Black has a brilliant tesuji to destroy White's corner. Where is it ? ENDCOM B 1 Q18 USER CORRECT ANSWER ENDUSER COM Correct Answer. Black 1 is a spectacular move. ENDCOM W 2 R17 COM If White plays 2, ... ENDCOM VAR W 2 P17 COM Variation. If White connects with 2, ... ENDCOM B 3 R17 COM ... Black can live with 3. White's corner territory is completely destroyed. <= ENDCOM ENDVAR B 3 P16 MARK A@Q16 B@P17 COM ... Black 3 threatens to link up with A or B. <= ENDCOM EVENT BOARDSIZE 19 SETUP W D18 F17 J17 R10 R17 Q17 P18 SETUP B C17 D16 D14 C10 O18 P17 N17 Q16 R16 MARK 1@P17 2@P18 3@O18 COM Problem 71. White to play. Black blocks with 1 and 3. What should White do now ? ENDCOM W 1 P16 USER CORRECT ANSWER ENDUSER COM Correct Answer. White should cut with 1. ENDCOM VAR W 1 S16 COM Failure. If White simply plays 1 ... ENDCOM B 2 S15 W 3 S17 COM ... and 3, ... ENDCOM B 4 P16 COM ... Black connects with 4. ENDCOM W 5 Q18 COM White lives with 5, but she ends in gote. <= ENDCOM ENDVAR B 2 O17 W 3 S16 B 4 S15 W 5 S17 B 6 R14 W 7 Q18 COM She can then live in the corner in sente with the moves to 7. ENDCOM B 8 P15 COM <= ENDCOM EVENT BOARDSIZE 19 SETUP W C16 E17 H17 C12 R10 Q18 SETUP B C10 K17 K15 Q17 R17 R15 MARK 1@Q18 COM Problem 72. This time, in answer to White 1, Black draws back into the corner with 2. How should White continue ? ENDCOM W 1 M17 USER CORRECT ANSWER ENDUSER COM Correct Answer. White should jump all the way to 1. ENDCOM B 2 M15 COM If Black caps with 2, ... ENDCOM W 3 K18 COM ... White attaches with 3. ENDCOM B 4 J18 COM If Black blocks with 4, ... ENDCOM W 5 L16 B 6 K16 W 7 L18 B 8 J17 W 9 P17 COM ... White plays the moves to 9. Black's moyo has been wiped out. <= ENDCOM EVENT BOARDSIZE 19 SETUP W K17 Q17 R14 C12 SETUP B D17 C14 H17 COM Problem 73. Black to play. Where should Black invade White's position on the right ? ENDCOM B 1 O17 USER CORRECT ANSWER ENDUSER COM Correct Answer. Black 1 aims at White's enclosure on the right. ENDCOM VAR B 1 M17 USER CORRECT ANSWER ENDUSER COM Correct Answer. Black 1 is also a vital point. ENDCOM W 2 O17 COM White will answer with 2 and ... ENDCOM B 3 L16 COM ... Black attacks the white stone on the left with 3. <= ENDCOM ENDVAR W 2 Q15 COM If White defends with 2, ... ENDCOM B 3 M17 W 4 K15 B 5 N14 COM ... the moves to 5 are the normal development. <= ENDCOM EVENT BOARDSIZE 19 SETUP W D18 F17 J17 R10 S17 S16 R17 Q17 Q18 P18 P16 SETUP B C17 D16 D14 C10 O18 P17 O17 N17 Q16 R16 R14 S15 MARK 8@P15 COM Problem 74. White to play. Black has omitted 8 in the Correct Answer of Problem 71. How should White continue ? ENDCOM W 1 P15 USER CORRECT ANSWER ENDUSER COM Correct Answer. White first exchanges 1 ... ENDCOM B 2 Q14 COM ... for 2, ... ENDCOM VAR B 2 M15 COM Failure. If Black jumps to 2, ... ENDCOM W 3 Q14 COM ... White attaches at 3. ENDCOM B 4 R15 COM If Black 4, ... ENDCOM W 5 R13 COM ... White 5 captures the black stones on the right. <= ENDCOM ENDVAR W 3 N15 COM ... then jumps to 3. Black is now separated into two weak groups. <= ENDCOM EVENT BOARDSIZE 19 SETUP W C16 E17 H17 C12 Q18 P17 R10 SETUP B C10 K17 K15 Q17 R17 R15 MARK 1@P17 COM Problem 75. Black to play. White 1 is a bad move. How does Black punish White ? ENDCOM B 1 N17 USER CORRECT ANSWER ENDUSER COM Correct Answer. Black should attack with 1. White's stones are heavy, with no room to expand. White cannot make sabaki as in Problem 66. <= ENDCOM EVENT BOARDSIZE 19 SETUP W C12 K17 O17 Q17 R14 H16 SETUP B D17 C14 H17 L16 M17 MARK 1@H16 COM Problem 76. Black to play. After Black 3 in the Variation Diagram of Problem 73, White attaches with 1. How does Black respond ? ENDCOM B 1 G17 USER CORRECT ANSWER ENDUSER COM Correct Answer. Black should draw back with 1. Next, ... ENDCOM VAR B 1 K16 USER CORRECT ANSWER ENDUSER COM Correct Answer. Black 1 and ... ENDCOM W 2 J17 B 3 G17 COM ... 3 are a bit inelegant, but they are playable. ENDCOM W 4 J16 B 5 K14 W 6 G16 B 7 F16 W 8 F15 B 9 E16 W 10 H13 COM The moves up to 10 are one variation. <= ENDCOM ENDVAR W 2 K16 B 3 L14 W 4 K15 B 5 L15 W 6 J13 B 7 L12 COM ... the moves to 7 can be expected. <= ENDCOM EVENT BOARDSIZE 19 SETUP W D17 D15 H17 H15 C10 R17 SETUP B K17 K15 Q16 Q10 MARK 1@R17 COM Problem 77. Black to play. Invading at 1, the 3-3 point, when Black has a stone on the star point, is usually the vital point. In which direction should Black play ? ENDCOM B 1 Q17 USER CORRECT ANSWER ENDUSER COM Correct Answer. Black should block at 2 ... ENDCOM VAR B 1 R16 COM Failure. Blocking from this side with 1 ... ENDCOM W 2 Q17 B 3 P17 W 4 P18 B 5 O17 W 6 O18 B 7 N17 W 8 S16 B 9 S15 W 10 S17 B 11 R14 MARK \t@K15 \t@K17 COM ... results in the joseki up to 11, but it leaves Black with a shallow moyo. <= ENDCOM ENDVAR W 2 R16 B 3 Q15 MARK \t@K15 \t@K17 COM ... and extend to 3 to make a box-like territory on the left. <= ENDCOM EVENT BOARDSIZE 19 SETUP W K17 Q17 R15 R10 SETUP B C16 E17 H17 COM Problem 78. Black to play. White has made wide extensions from her corner enclosure at the top right. However, White's position is thin and vulnerable. Where should Black invade ? ENDCOM B 1 M17 USER CORRECT ANSWER ENDUSER COM Correct Answer. Black 1 is the correct invasion point. ENDCOM W 2 K15 VAR W 2 L16 COM Variation. White might also attack with 2. ENDCOM B 3 P17 COM Black would then attach with 3 and, ... ENDCOM VAR B 3 N15 COM If Black 3 here, ... ENDCOM W 4 O17 COM ... White would attack at 4. <= ENDCOM ENDVAR W 4 Q16 B 5 Q18 COM ... after 5, ... ENDCOM W 6 R18 B 7 N15 COM ... jump to 7. <= ENDCOM ENDVAR B 3 M15 W 4 K13 MARK 2@K15 COM If White jumps to 2 and 4, ... ENDCOM B 5 M13 MARK 3@M15 COM ... Black follows her into the center with 3 and 5. <= ENDCOM EVENT BOARDSIZE 19 SETUP W C12 K17 Q17 R14 P15 SETUP B D17 C14 H17 O17 MARK 2@P15 1@O17 COM Problem 79. Black to play. Suppose White answers the invasion of Black 1 with 2. How does Black continue ? ENDCOM B 1 O15 USER CORRECT ANSWER ENDUSER COM Correct Answer. Black exchanges 1 ... ENDCOM W 2 P14 COM ... for 2, ... ENDCOM VAR W 2 O14 MARK 1@O15 COM Variation. White could answer 1 with 2 ... ENDCOM B 3 N15 W 4 K15 COM ... and jump to 4. ENDCOM B 5 P16 COM Black would then play 5, ... ENDCOM W 6 Q16 COM ... followed by White 6. ENDCOM VAR W 6 Q15 MARK 5@P16 COM White could also answer 5 with 6 here, but her shape in this corner is full of holes. <= ENDCOM ENDVAR B 7 P14 COM If the ladder is favourable, Black would atari at 7 ... ENDCOM W 8 Q15 B 9 O13 COM ... and 9. <= ENDCOM ENDVAR B 3 K15 COM ... then caps with 3. Black's moves flow very beautifully. <= ENDCOM EVENT BOARDSIZE 19 SETUP W D17 D15 C10 H17 H15 R17 R16 SETUP B K17 K15 Q17 Q16 Q15 Q10 MARK 1@Q15 COM Problem 80. White to play. After Black extends to 1, what should White do ? ENDCOM W 1 R15 USER CORRECT ANSWER ENDUSER COM Correct Answer. There are two Correct Answers. Crawling with White 1 here is the first one. <= ENDCOM VAR W 1 S14 USER CORRECT ANSWER ENDUSER COM Correct Answer. The knight's move of White 1 is the other answer. <= ENDCOM ENDVAR VAR W 1 R14 COM Failure. White 1 here is a mistake. <= ENDCOM ENDVAR EVENT BOARDSIZE 19 SETUP W K17 L16 Q17 P16 R15 R10 SETUP B C16 E17 H17 M17 P17 MARK 1@P16 COM Problem 81. Black to play. How should Black answer the hane of White 1 ? ENDCOM B 1 Q18 USER CORRECT ANSWER ENDUSER COM Correct Answer. The hane of Black 1 is the best response. ENDCOM VAR B 1 O17 COM Failure. If Black immediately draws back with 1 here, ... ENDCOM W 2 Q18 COM ... White will descend to 2. ENDCOM B 3 N15 COM This result is better for White than the one in the Correct Answer. <= ENDCOM ENDVAR W 2 Q16 COM After White connects at 2, ... ENDCOM B 3 O17 W 4 R18 B 5 N15 MARK 3@O17 COM ... Black makes shape with 3 and 5. <= ENDCOM EVENT BOARDSIZE 19 SETUP W C12 K17 M17 Q17 R14 SETUP B D17 C14 H17 O17 MARK 2@M17 1@O17 COM Problem 82. Black to play. White pincers the marked Black stone with 2. If you've never seen it before, Black's next move might surprise you. ENDCOM B 1 Q15 USER CORRECT ANSWER ENDUSER COM Correct Answer. Black 1 is an interesting move. There are other moves, such as attaching at A or B. However, you should not neglect to learn the variation starting with Black 1. <= ENDCOM VAR B 1 O15 COM Failure. Simply jumping out with Black 1 ... ENDCOM W 2 Q15 COM ... lets White defend the corner with 2. This is a steady move and there are no longer any weaknesses in White's position. <= ENDCOM ENDVAR VAR B 1 Q16 USER CORRECT ANSWER ENDUSER COM Correct Answer. Also possible. <= ENDCOM ENDVAR VAR B 1 R17 USER CORRECT ANSWER ENDUSER COM Correct Answer. Also possible. <= ENDCOM ENDVAR EVENT BOARDSIZE 19 SETUP W D17 D15 C10 H17 H15 R17 R16 R14 SETUP B K17 K15 Q17 Q16 Q15 Q10 MARK 1@R14 COM Problem 83. Black to play. As mentioned in Problem 80, White 1 is a bad move. How does Black punish White ? ENDCOM B 1 R15 USER CORRECT ANSWER ENDUSER COM Correct Answer. Black plays 1 ... ENDCOM W 2 S15 B 3 S16 COM ... and 3. ENDCOM VAR B 3 S14 COM Failure. Cutting below with 3 is a mistake. ENDCOM W 4 S13 COM White ataris with 4 and will get a ponnuki along the side. See the next Problems for the continuation. <= ENDCOM ENDVAR W 4 S17 COM If White 4, ... ENDCOM VAR W 4 S14 COM Failure for White. White 4 here is bad. <= ENDCOM ENDVAR B 5 S14 COM ... Black ataris at 5, ... ENDCOM W 6 T16 B 7 R13 COM ... then catches a stone in a ladder with 7, confining White to the corner. Black also gets a thick wall. <= ENDCOM EVENT BOARDSIZE 19 SETUP W M17 Q17 R15 C14 D14 C11 SETUP B D16 C15 F16 K17 COM Problem 84. Black to play. White's three-space extension from her corner enclosure is ideal. However, Black has a strong position on the left. How should Black invade ? ENDCOM B 1 O17 USER CORRECT ANSWER ENDUSER COM Correct Answer. Black should invade at 1. ENDCOM VAR B 1 P17 COM Failure. Attaching with 1 ... ENDCOM W 2 Q16 B 3 Q18 W 4 R18 B 5 N16 W 6 M16 B 7 N15 MARK 5@N16 COM ... and trying to escape with 5 and 7 is not good. ENDCOM W 8 N17 MARK 6@M16 COM Black's shape is destroyed when White plays 6 and 8. <= ENDCOM ENDVAR W 2 M15 COM If White jumps out with 2, ... ENDCOM B 3 O15 COM ... Black escapes into the center with 3. <= ENDCOM EVENT BOARDSIZE 19 SETUP W C12 K17 M17 Q17 R15 R14 SETUP B D17 C14 H17 O17 Q15 MARK 2@R15 1@Q15 COM Problem 85. Black to play. Against the shoulder hit of Black 1, White responds with 2. What should Black do now ? ENDCOM B 1 Q18 USER CORRECT ANSWER ENDUSER COM Correct Answer. Black 1 is a brilliant move. However White answers, Black has an effective continuation. <= ENDCOM VAR B 1 Q16 COM Failure. Forcing with Black 1 ... ENDCOM W 2 R16 B 3 P17 COM ... and 3 is unimaginative. ENDCOM W 4 Q18 COM White's corner territory becomes large and impregnable after White descends to 4. <= ENDCOM ENDVAR EVENT BOARDSIZE 19 SETUP W D17 D15 C10 H17 H15 R17 R16 S15 SETUP B K17 K15 Q17 Q16 R15 S14 Q10 MARK 3@S14 2@S15 1@R15 COM Problem 86. White to play. Black aggressively blocks with 3. How should White respond ? ENDCOM W 1 R14 USER CORRECT ANSWER ENDUSER COM Correct Answer. White should atari with 1 ... ENDCOM VAR W 1 Q18 USER CORRECT ANSWER ENDUSER COM Correct Answer. White could also play 1 here, but this is a difficult variation. <= ENDCOM ENDVAR B 2 Q15 W 3 S13 COM ... and 3. This is the same as the Failure Diagram in Problem 83. <= ENDCOM B 4 S16 VAR B 4 Q14 COM Black could also atari at 4. Either way, White will have no problems. <= ENDCOM ENDVAR W 5 T14 B 6 S17 MARK 4@S16 COM Black captures two stones with 4 and 6. <= ENDCOM EVENT BOARDSIZE 19 SETUP W M17 N16 Q17 R15 C14 D14 C11 SETUP B C15 D16 F16 K17 O17 MARK \t@O17 1@N16 COM Problem 87. Black to play. What should Black do when White tries to enclosure the marked stone with the diagonal move of 1 ? ENDCOM B 1 P16 USER CORRECT ANSWER ENDUSER COM Correct Answer. Black should answer with 1. ENDCOM VAR B 1 O16 COM Failure. Black 1 is bad. ENDCOM W 2 O15 B 3 P15 VAR B 3 Q16 COM If Black plays 3 here, ... ENDCOM W 4 R16 B 5 P15 W 6 Q15 B 7 P16 W 8 P14 COM ... the moves to White 8 follow and Black's stones are almost dead. <= ENDCOM ENDVAR W 4 P16 MARK 2@O15 COM White confines the black stones to the top with 2 and 4. <= ENDCOM ENDVAR W 2 O15 COM If White continues with 2, ... ENDCOM B 3 Q16 W 4 R16 B 5 R17 MARK 3@Q16 COM ... Black pushes through and cuts with 3 and 5, ... ENDCOM W 6 Q18 B 7 P14 MARK 5@R17 A@P15 COM ... then jumps to 7. White cannot push through at A because of the aji of 5. <= ENDCOM EVENT RESULT Draw BOARDSIZE 19 SETUP W C12 K17 M17 Q17 R17 R15 R14 SETUP B D17 C14 H17 O17 Q18 Q15 MARK 2@R17 1@Q18 COM Problem 88. Black to play. White draws back with 2 in answer to Black 1. How does Black play next ? ENDCOM B 1 O15 MARK A@P17 USER CORRECT ANSWER ENDUSER COM Correct Answer. Black should make shape by jumping to 1. If Black gets to play at A later, he will have made a wonderful shape. <= ENDCOM VAR B 1 P17 COM Failure. If Black rushes to play 1, ... ENDCOM W 2 O15 COM ... White strikes at 2. Clearly, this is the vital point of the whole position. <= ENDCOM ENDVAR EVENT BOARDSIZE 19 SETUP W D17 D15 H17 H15 C10 R17 R16 S15 R14 S13 T14 SETUP B K17 K15 Q17 Q16 Q15 R15 S16 S17 Q10 COM Problem 89. White to play. This is a continuation of Problem 86. How should White play ? ENDCOM W 1 Q14 USER CORRECT ANSWER ENDUSER COM Correct Answer. Pushing up with 1 is the vital point. ENDCOM B 2 P14 COM Black blocks at 2 ENDCOM W 3 P13 B 4 O14 W 5 O13 B 6 N14 MARK 5@O13 3@P13 COM If the thickness White gets on the right side is worth the territory Black gets at the top, she may play 3 and 5. <= ENDCOM EVENT BOARDSIZE 19 SETUP W C14 D14 C11 M17 N16 N14 Q17 Q16 R15 SETUP B C15 D16 F16 K17 O17 P16 P15 MARK 3@N14 2@P15 1@Q16 COM Problem 90. Black to play. Continuing from Problem 87, White defends at 1 and jumps to 3. How should Black answer ? ENDCOM B 1 P13 USER CORRECT ANSWER ENDUSER COM Correct Answer. Black should simply jump to 1 and, ... ENDCOM VAR B 1 R14 USER CORRECT ANSWER ENDUSER COM Correct Answer. Black could also attach at 1. ENDCOM W 2 Q15 COM If White 2, ... ENDCOM B 3 P14 W 4 Q14 B 5 P13 W 6 Q13 B 7 P12 COM ... Black and White move down the right side with the moves to 7. White's stones on the left now fall in the shadow of Black's thick wall. <= ENDCOM ENDVAR W 2 R13 COM ... after White defends the right side with 2, ... ENDCOM B 3 O12 COM ... play the diagonal move of 3. <= ENDCOM EVENT BOARDSIZE 19 SETUP W C12 K17 M17 Q17 Q16 R15 R14 SETUP B D17 C14 H17 O17 Q18 Q15 MARK 2@Q16 1@Q18 COM Problem 91. Black to play. What does Black do if White answers 1with 2 ? ENDCOM B 1 R18 USER CORRECT ANSWER ENDUSER COM Correct Answer. Wrenching the corner territory away from White with 1 is the natural move. ENDCOM VAR B 1 P18 COM Failure. If Black draws back with 1, ... ENDCOM W 2 R18 COM ... White takes the corner with 2 and Black's shape has been destroyed. <= ENDCOM ENDVAR W 2 O16 COM Next, White attaches with 2. ENDCOM B 3 P17 W 4 P16 B 5 S16 COM Black's invasion is a success. <= ENDCOM EVENT BOARDSIZE 19 SETUP W D17 D15 H17 H15 C10 R17 R16 S15 T14 R14 Q14 P13 S13 SETUP B K17 K15 Q17 Q16 Q15 R15 S16 S17 P14 O13 MARK 3@O13 2@P13 1@P14 COM Problem 92. White to play. Black 3 is an overplay. How does White take advantage of it ? ENDCOM W 1 R18 USER CORRECT ANSWER ENDUSER COM Correct Answer. White should descend to 1. ENDCOM B 2 Q18 COM If Black 2, ... ENDCOM VAR B 2 S18 COM Failure. If Black saves his corner with 2, ... ENDCOM W 3 Q18 COM ... White turns at 3. ENDCOM B 4 P18 COM After 4, ... ENDCOM W 5 P15 MARK B@P17 A@O14 COM ... White ataris at 5, threatening to capture one stone at A or four stones at B. <= ENDCOM ENDVAR W 3 S18 COM ... White will play 3, capturing two stones in the corner. <= ENDCOM EVENT BOARDSIZE 19 SETUP W M17 N16 P14 R15 Q17 SETUP B C15 D16 F16 K17 P16 O17 MARK 1@P14 \t@P16 COM Problem 93. Black to play. This time White caps the marked stone with 1. How does Black answer ? ENDCOM B 1 O15 USER CORRECT ANSWER ENDUSER COM Correct Answer. Black should poke through the hole with 1. Black's shape looks bad, but White is unable to counter effectively. ENDCOM W 2 O16 B 3 P17 W 4 P15 MARK 2@O16 COM If White tries to take advantage of Black's bad shape with 2 and 4, ... ENDCOM B 5 Q16 W 6 R16 B 7 R17 W 8 S17 B 9 R18 W 10 S18 B 11 Q18 MARK B@Q15 A@O14 COM ... Black lives in the corner with the moves to 11. Black now has moves at A and B. <= ENDCOM EVENT BOARDSIZE 19 SETUP W C12 K17 M17 Q17 R18 R15 R14 SETUP B D17 C14 H17 O17 Q18 Q15 MARK 2@R18 1@Q18 COM Problem 94. Black to play. White answers Black 1 by blocking at 2. What should Black do ? ENDCOM B 1 Q16 USER CORRECT ANSWER ENDUSER COM Correct Answer. Black 1 is the vital point. <= ENDCOM VAR B 1 P17 MARK @@Q16 COM Failure. Of course, Black would like to play at 1, but he cannot do so unless he has played @ in the Correct Answer. ENDCOM W 2 Q16 COM Now White takes the point 2, and Black's shape has collapsed. <= ENDCOM ENDVAR EVENT BOARDSIZE 19 SETUP W D17 D15 H17 H15 C10 R17 R16 S15 R14 S13 SETUP B K17 K15 Q17 Q16 Q15 R15 S14 Q14 Q10 MARK 1@Q14 A@S16 COM Problem 95. White to play. Instead of an atari at A, Black might atari from above with 1. What should White do ? ENDCOM W 1 T14 USER CORRECT ANSWER ENDUSER COM Correct Answer. White should capture with 1. ENDCOM VAR W 1 R13 COM Failure. If White connects with 1, ... ENDCOM B 2 S16 W 3 T14 B 4 S17 MARK 2@S16 COM ... Black will take the corner with 2 and 4. Compared to the joseki in Problem 86, this is a failure for White. <= ENDCOM ENDVAR B 2 R13 COM If Black ataris at 2 next, ... ENDCOM W 3 S14 COM ... White will connect. <= ENDCOM EVENT BOARDSIZE 19 SETUP W C14 D14 C11 M17 N16 P14 Q17 Q16 R15 SETUP B C15 D16 F16 K17 P16 O17 O15 MARK 1@Q16 COM Problem 96. Black to play. White defends the corner with 1. What is Black's response ? ENDCOM B 1 P15 USER CORRECT ANSWER ENDUSER COM Correct Answer. Black first exchanges 1 ... ENDCOM W 2 Q14 COM ... for White 2, ... ENDCOM B 3 L16 COM ... then plays on the vital point of 3, attacking the two white stones. ENDCOM W 4 N15 COM Both White and Black must now move into the center with the moves from 4. ENDCOM B 5 O14 W 6 N14 B 7 O13 W 8 N13 B 9 O12 COM After 9, however, it is Black who has the better position. <= ENDCOM EVENT BOARDSIZE 19 SETUP W C12 K17 M17 Q17 R18 R16 R15 SETUP B D17 C14 H17 O17 Q18 Q16 Q15 R14 MARK 2@R16 1@Q16 COM Problem 97. Black to play. What should Black do after White answers Black 1 with White 2 ? Show the next three moves. ENDCOM B 1 P17 USER CORRECT ANSWER ENDUSER COM Correct Answer. This problem is probably too easy. Playing atari is obvious, ... ENDCOM W 2 R17 B 3 O15 COM ... and it is common sense to make shape with 3. <= ENDCOM VAR B 3 N15 COM Failure. Black 3 is a false tesuji. ENDCOM W 4 K15 MARK B@O15 A@Q14 COM White answers by jumping to 4, but late White will come back and play A. At this point Black will wish he had played at B, the vital point in all these variations. <= ENDCOM ENDVAR EVENT BOARDSIZE 19 SETUP W D17 D15 H17 H15 C10 R17 R16 R15 S14 SETUP B K17 K15 Q17 Q16 Q15 R14 S13 Q10 MARK 5@S13 4@S14 3@R14 2@R15 1@Q15 COM Problem 98. White to play. As we saw in Problem 80, White 2 is the correct response to Black 1. If Black now blocks with 3 and 5, what should White do ? ENDCOM W 1 R13 USER CORRECT ANSWER ENDUSER COM Correct Answer. There is no other way but to atari with White 1 ... ENDCOM VAR W 1 S15 COM Failure. If White timidly connects with 1, ... ENDCOM B 2 R13 COM ... Black connects with 2 and his thickness on the outside is overwhelming. <= ENDCOM ENDVAR B 2 Q14 W 3 S12 COM ... and 3. <= ENDCOM EVENT BOARDSIZE 19 SETUP W D18 F17 H16 K16 N17 N15 P15 SETUP B C17 D16 D14 C10 P17 R16 Q14 Q12 MARK 2@Q14 1@P15 COM Problem 99. White to play. After the exchange of White 1 for Black 2, Black's position looks very strong. However, there is a way for White to launch a successful invasion. ENDCOM W 1 R17 USER CORRECT ANSWER ENDUSER COM Correct Answer. White 1 is a tesuji. ENDCOM B 2 S17 COM If Black blocks at 2, ... ENDCOM VAR B 2 Q16 COM Variation. If Black plays 2, ... ENDCOM W 3 Q18 B 4 P18 W 5 S16 B 6 S15 W 7 S18 B 8 T16 W 9 T17 COM ... White can live in the corner with a ko by playing the moves to 9. ENDCOM B 10 S17 COM <= ENDCOM ENDVAR W 3 S16 COM ... White crosscuts with 3. Next, ... ENDCOM B 4 R18 COM ... if Black 4, ... ENDCOM VAR B 4 S15 COM ... if Black 4, ... ENDCOM W 5 Q16 COM ... White 5. White has succeeded. <= ENDCOM ENDVAR W 5 R15 COM ... White 5. <= ENDCOM EVENT BOARDSIZE 19 SETUP W C12 K17 M17 Q17 R17 R18 R15 R14 SETUP B D17 C14 H17 O17 Q18 Q16 Q15 MARK 2@R17 1@Q16 COM Problem 100. Black to play. This time White solidly connects with 2 after Black 1. How does Black respond ? ENDCOM B 1 O15 MARK \t@Q15 \t@Q16 \t@Q18 \t@R18 \t@R17 \t@R15 USER CORRECT ANSWER ENDUSER COM Correct Answer. Again Black 1 is the vital point. Black's success can be measured by the fact that his three marked stones have forced White to make three submissive moves, shown by the three marked white stones. <= ENDCOM VAR B 1 P17 COM Failure. Of course, Black would like to play 1, ... ENDCOM W 2 O15 COM ... but White would then hit him at the vital point of 2, destroying his shape. <= ENDCOM ENDVAR EVENT BOARDSIZE 19 SETUP W D15 D17 H17 H15 C10 R17 R16 R15 S14 R13 S12 SETUP B K17 K15 Q17 Q16 Q15 R18 S13 R14 Q14 Q10 MARK 1@R18 B@S15 A@S18 COM Problem 101. White to play. After White 3 in the Correct Answer of Problem 98, Black 1 is the vital point. If White blocks at A, Black will atari at B. What should White do ? ENDCOM W 1 T13 USER CORRECT ANSWER ENDUSER COM Correct Answer. Capturing with 1 leaves White with good aji. ENDCOM VAR W 1 S16 COM Failure. White could also respond with 1, ... ENDCOM B 2 Q13 COM ... but Black ataris with 2. Black is putting all his stones to good use. <= ENDCOM ENDVAR B 2 S17 W 3 S16 B 4 T16 MARK 2@S17 COM Black gets to play forcing moves with 2 and 4, ... ENDCOM W 5 S15 COM ... but that cannot be helped. <= ENDCOM EVENT BOARDSIZE 19 SETUP W D18 F17 H16 K16 N17 N15 P15 R17 SETUP B C17 D16 D14 C10 P17 Q17 R16 Q14 Q12 MARK 1@Q17 COM Problem 102. White to play. You must also be prepared for Black's move at 1. How should White respond ? ENDCOM W 1 S16 USER CORRECT ANSWER ENDUSER COM Correct Answer. The hane of White 1 is the correct move. ENDCOM B 2 R15 COM If Black 2, ... ENDCOM VAR B 2 R18 COM Variation. If Black takes the corner with 2, ... ENDCOM W 3 R15 COM ... White ataris with 3 and ... ENDCOM B 4 S17 W 5 Q15 COM ... connects with 5. Black gets the corner, but White has invaded the right side. <= ENDCOM ENDVAR W 3 R18 COM ... White lives in the corner by extending to 3. <= ENDCOM EVENT BOARDSIZE 19 SETUP W C12 K17 M17 K15 Q17 R17 R18 R15 R14 SETUP B D17 C14 H17 O17 O15 Q18 Q16 Q15 MARK 2@K15 1@O15 COM Problem 103. Black to play. After Black 1, White reinforces her stones in the center with 2. How should Black continue his operations in the top right ? ENDCOM B 1 R16 USER CORRECT ANSWER ENDUSER COM Correct Answer. Black should push through and ... ENDCOM W 2 S16 B 3 S17 MARK 1@R16 COM ... cut with 1 and 3. However White responds, Black will gain an advantage. c<= ENDCOM VAR B 3 S15 COM Failure. Black suffers a loss if he cuts on the other side with 3. The reason will become clear in the next few problems. ENDCOM W 4 S14 COM White ataris with 4. <= ENDCOM ENDVAR EVENT BOARDSIZE 19 SETUP W K15 Q17 R15 SETUP B D16 D14 C10 H16 K17 MARK 1@K15 2@H16 COM Problem 104. White to play. White flattens Black's moyo at the top left by exchanging 1 for Black 2. How should White continue ? ENDCOM W 1 C17 USER CORRECT ANSWER ENDUSER COM Correct Answer. It is urgent for White to invade at the 3-3 point. If White neglects to play here - (see Variation to this move) <= ENDCOM VAR W 1 K10 COM (White 1 is played here to get 'Black to move'). ENDCOM B 2 D17 COM Black will add another stone at 2. All the territory in the top left part of the board will become Black's. <= ENDCOM ENDVAR EVENT BOARDSIZE 19 SETUP W P17 R16 SETUP B K17 N17 R14 R11 COM Problem 105. Black to play. The small-knight enclosure secures the corner, but if Black has built strong positions around it, an invasion is possible. Where should Black invade ? ENDCOM B 1 Q17 USER CORRECT ANSWER ENDUSER COM Correct Answer. Black 1 is the point to gauge out White's base. ENDCOM VAR B 1 PASS ENDVAR W 2 Q16 B 3 R17 W 4 P16 VAR W 4 Q18 COM Failure. White might respond with 4 ... ENDCOM B 5 R18 W 6 P18 COM ... and 6 here. ENDCOM B 7 S16 W 8 S15 B 9 S17 W 10 R15 COM However, after she defends with 10, ... ENDCOM B 11 P16 COM ... Black cuts with 11 and White's position collapses. <= ENDCOM ENDVAR B 5 S16 W 6 S15 B 7 S17 W 8 R15 B 9 S14 W 10 T15 B 11 P18 W 12 O18 B 13 Q18 COM Up to 13, Black lives in the corner. ENDCOM W 14 O17 B 15 N18 COM After 15, however, White's group is eyeless and will become a target of attack. <= ENDCOM EVENT BOARDSIZE 19 SETUP W C12 K17 K15 M17 Q17 R17 R18 S16 S15 R15 R14 SETUP B D17 C14 H17 O17 Q18 S17 Q15 Q16 R16 O15 MARK 2@S15 1@S17 COM Problem 106. Black to play. White answers the cut of Black 1 with 2. What should Black do now ? ENDCOM B 1 S18 USER CORRECT ANSWER ENDUSER COM Correct Answer. Black should play 1. ENDCOM VAR B 1 P17 COM Failure. Black 1 also makes shape, ... ENDCOM W 2 S18 COM ... but after White 2, there is no play left for Black in the corner. See the next problem for amplification. <= ENDCOM ENDVAR W 2 P18 COM White has no choice but to atari with 2. ENDCOM VAR W 2 P17 COM If White plays 2 here, ... ENDCOM B 3 P18 COM ... Black plays 3 and the white stones will be captured. <= ENDCOM ENDVAR B 3 P17 COM Now Black can make good shape by playing atari with 3. <= ENDCOM EVENT BOARDSIZE 19 SETUP W C17 K15 Q17 R15 SETUP B D17 D16 D14 C10 H16 K17 MARK 1@D17 COM Problem 107. White to play. Against White's invasion, Black blocks with 1. How does White respond ? ENDCOM W 1 B16 USER CORRECT ANSWER ENDUSER COM Correct Answer. White 1 is the Correct Answer. ENDCOM VAR W 1 C16 COM Failure. White 1 is a bad move. ENDCOM B 2 C15 COM Black blocks with 2 and, ... ENDCOM W 3 D18 B 4 E18 W 5 C18 B 6 B16 COM ... after 6, White has no room to make two eyes. <= ENDCOM ENDVAR B 2 B14 COM Black confines White to the corner with 2, ... ENDCOM W 3 D18 B 4 E18 W 5 B18 B 6 D19 W 7 C18 COM ... but White lives up to 7. <= ENDCOM EVENT BOARDSIZE 19 SETUP W K17 P16 R16 SETUP B D17 D15 H17 R13 R10 COM Problem 108. Black to play. Where should Black attack White's moyo at the top ? ENDCOM B 1 M17 USER CORRECT ANSWER ENDUSER COM Correct Answer. Black 1 is the vital point. ENDCOM W 2 L16 COM If White 2, ... ENDCOM VAR W 2 O17 COM Variation. If White defends the corner with 2, ... ENDCOM B 3 L16 COM ... Black will play 3, and the lone stone on the left will come under attack. <= ENDCOM ENDVAR B 3 O17 COM ... Black forces with 3, ... ENDCOM W 4 P17 B 5 N15 COM ... then jumps to 5. Black has made light sabaki. <= ENDCOM EVENT BOARDSIZE 19 SETUP W C12 K17 K15 M17 P18 Q19 R18 R17 Q17 S16 S15 R15 R14 SETUP B D17 C14 H17 O17 P17 S18 S17 Q15 Q16 R16 O15 MARK 1@Q19 A@Q18 COM Problem 109. Black to play. White has captured the black stone at A captures with 1. What should Black do now ? ENDCOM B 1 S19 USER CORRECT ANSWER ENDUSER COM Correct Answer. Black should play 1 ... ENDCOM VAR B 1 O18 COM Failure. Simply playing Black 1 is lukewarm. ENDCOM W 2 S19 COM White plays 2 and there is no longer any danger to her stones in the corner. <= ENDCOM ENDVAR W 2 R19 VAR W 2 O18 COM If White 2, ... ENDCOM B 3 R19 COM ... Black plays 3 and White collapses. <= ENDCOM ENDVAR B 3 O18 COM ... and 3, ... ENDCOM W 4 T17 MARK B@N19 A@O19 COM ... then leave the situation as it is. After 4, Black A (or Black B, threatening ko) could later become double threats against the white groups on the left and the right. <= ENDCOM EVENT BOARDSIZE 19 SETUP W C17 B16 K15 Q17 R15 SETUP B C16 D16 D17 D14 C10 H16 K17 MARK 1@C16 \t@B16 COM Problem 110. White to play. In answer to the marked white stone, Black plays 1. How does White respond to this move ? ENDCOM W 1 B18 USER CORRECT ANSWER ENDUSER COM Correct Answer. White 1 makes good shape. ENDCOM VAR W 1 C18 COM Failure. White can live with 1 here also, but it is not good. ENDCOM B 2 B15 W 3 A17 B 4 D18 W 5 B18 COM White's territory in the corner is small. <= ENDCOM ENDVAR B 2 B15 COM If Black 2, ... ENDCOM W 3 D18 COM ... White plays 3. <= ENDCOM EVENT BOARDSIZE 19 SETUP W L17 P16 R16 B16 C14 C11 SETUP B C17 D16 F16 J17 COM Problem 111. Black to play. White's extension is one space narrower than in Problem 108. Where should Black invade ? ENDCOM B 1 N17 USER CORRECT ANSWER ENDUSER COM Correct Answer. Black 1 is the vital point. We will look at the variations in the next few problems. <= ENDCOM VAR B 1 Q17 MARK @@N17 USER CORRECT ANSWER ENDUSER COM Correct Answer. Black could also peep at 1. However, Black @ in the Correct Answer is the usual move. <= ENDCOM ENDVAR VAR B 1 M17 USER CORRECT ANSWER ENDUSER COM Correct Answer. Attaching at Black 1 is also possible. <= ENDCOM ENDVAR EVENT BOARDSIZE 19 SETUP W C12 K15 K17 M17 S18 R18 R17 Q17 S16 R15 R14 SETUP B D17 C14 H17 O15 O17 Q15 Q16 R16 S17 Q18 MARK 2@S18 1@S17 COM Problem 112. Black to play. To avoid the threats in Problem 109, White plays 2. What is Black's response ? ENDCOM B 1 S15 USER CORRECT ANSWER ENDUSER COM Correct Answer. Black ataris with 1, ... ENDCOM VAR B 1 O13 USER CORRECT ANSWER ENDUSER COM Correct Answer. Black may not want to play the moves in the Correct Answer immediately. He could first jump to 1 to eliminate any danger to his group. ENDCOM W 2 H15 B 3 S15 W 4 T17 B 5 R13 MARK 3@S15 COM After that, he plays 3 and 5, looking on these as forcing moves. ENDCOM W 6 S14 B 7 F17 COM <= ENDCOM ENDVAR W 2 T17 B 3 R13 COM ... then makes the nose attachment of 3. ENDCOM W 4 S14 COM If White 4, ... ENDCOM B 5 Q14 COM ... Black presses from above with 5. <= ENDCOM EVENT BOARDSIZE 19 SETUP W B18 B17 C17 B16 K15 Q17 R15 SETUP B C18 D18 D17 D16 C16 D14 H16 K17 C10 MARK 3@D18 2@B17 1@C18 COM Problem 113. White to play. Black ataris with 1, then connects with 3. How should White play ? ENDCOM W 1 B14 USER CORRECT ANSWER ENDUSER COM Correct Answer. Jumping to 1 is correct. ENDCOM VAR W 1 B15 COM Failure. If White simply extends to 1, ... ENDCOM B 2 B14 COM ... Black kills her with 2. <= ENDCOM ENDVAR B 2 B13 COM After Black 2, ... ENDCOM W 3 B19 B 4 C14 W 5 B15 MARK 3@B19 COM ... White plays in the corner with 3 and 5, and she is alive. <= ENDCOM EVENT BOARDSIZE 19 SETUP W L17 P16 R16 M16 B16 C14 C11 SETUP B C17 D16 F16 J17 N17 MARK 1@M16 COM Problem 114. Black to play. How does Black answer the diagonal move of White 1 ? ENDCOM B 1 Q17 USER CORRECT ANSWER ENDUSER COM Correct Answer. Black hits the vital point of the one-space enclosure with 1, ... ENDCOM VAR B 1 P17 USER CORRECT ANSWER ENDUSER COM Correct Answer. Black 1 is a move for special situations. ENDCOM W 2 Q17 COM White answers with 2, ... ENDCOM B 3 O16 COM ... and Black expands with 3. <= ENDCOM ENDVAR W 2 R17 B 3 P17 W 4 Q16 B 5 N16 W 6 N15 B 7 L18 W 8 K18 B 9 M18 W 10 K17 B 11 O18 COM ... then lives with the moves to 11. <= ENDCOM VAR B 11 J18 MARK @@O18 COM Instead of @, Black could also play 11 here. <= ENDCOM ENDVAR EVENT BOARDSIZE 19 SETUP W C12 K17 M17 P17 Q17 R17 R18 R15 R14 SETUP B D17 C14 H17 O17 Q16 Q15 O15 Q18 MARK A@O16 2@P17 1@O15 COM Problem 115. Black to play. In answer to Black 1, White plays 2, hoping that Black will submissively answer at A. How does Black take the initiative in this position ? ENDCOM B 1 N17 USER CORRECT ANSWER ENDUSER COM Correct Answer. Black should play 1 ... ENDCOM W 2 M16 B 3 N15 MARK A@L14 COM ... and 3. aiming to attack the white stones with A. <= ENDCOM W 4 L14 COM If White defends with 4, ... ENDCOM B 5 R16 W 6 S16 B 7 S17 W 8 S15 B 9 P18 MARK 5@R16 7@S17 COM ... Black forces with the moves to 9, ... ENDCOM W 10 S18 B 11 N12 COM ... then jumps to 11. Black has made a beautiful sabaki. <= ENDCOM EVENT BOARDSIZE 19 SETUP W C17 D18 C16 K15 Q17 R15 SETUP B D17 D16 E18 C15 D14 C10 H16 K17 MARK 4@E18 3@D18 2@C15 1@C16 COM Problem 116. White to play. After Black 4, White can't live unconditionally. Where does White play to get a ko ? ENDCOM W 1 B18 USER CORRECT ANSWER ENDUSER COM Correct Answer. The only move for White is 1. ENDCOM B 2 D19 COM After Black 2, ... ENDCOM VAR B 2 B16 COM Failure. If Black 2, ... ENDCOM W 3 B17 B 4 B15 W 5 C19 MARK 3@B17 COM ... White can live unconditionally with 3 and 5. <= ENDCOM ENDVAR W 3 C19 COM ... White must pin her hopes on a ko by playing 3. <= ENDCOM EVENT BOARDSIZE 19 SETUP W L17 M16 P16 R16 P17 B16 C14 C11 SETUP B C17 D16 F16 J17 N17 Q17 MARK 1@Q17 2@P17 COM Problem 117. Black to play. In answer to Black 1, White blocks on the other side with 2. How should Black respond ? ENDCOM B 1 Q16 USER CORRECT ANSWER ENDUSER COM Correct Answer. Black makes life in the corner ... ENDCOM W 2 Q15 B 3 R17 W 4 R15 MARK 3@R17 VAR W 4 P15 COM Variation. When Black plays 3, White could connect at 4, ... ENDCOM B 5 S15 COM ... but Black 5 becomes a tesuji. <= ENDCOM VAR B 5 P18 COM Black could also play 5 here first, ... ENDCOM W 6 O18 B 7 Q18 W 8 O17 B 9 S15 COM ... then come back and play 9. <= ENDCOM ENDVAR ENDVAR B 5 P18 W 6 O18 B 7 Q18 W 8 O17 B 9 S16 W 10 S15 B 11 S17 MARK A@P15 COM ... with the moves to 11. White must now defend against the cut at A. <= ENDCOM EVENT BOARDSIZE 19 SETUP W C15 D16 F16 J17 M17 R14 R11 SETUP B O17 O15 R16 C14 D14 D11 COM Problem 118. White to play. Black's position at the top is vulnerable. Where should White invade ? ENDCOM W 1 R17 USER CORRECT ANSWER ENDUSER COM Correct Answer. White 1 is the vital point. ENDCOM B 2 Q16 COM If Black 2, ... ENDCOM VAR B 2 Q17 COM Variation. If Black blocks with 2, ... ENDCOM W 3 S17 B 4 S16 W 5 Q18 MARK A@Q16 3@S17 COM ... White will play 3 and 5. Since White has the cutting point of A, she can live. <= ENDCOM ENDVAR W 3 S16 B 4 S15 W 5 S17 B 6 R15 W 7 P18 COM ... White lives with the moves to 7. <= ENDCOM EVENT BOARDSIZE 19 SETUP W C16 E16 H17 C12 Q14 R14 R11 SETUP B C10 K17 O16 Q16 R15 COM Problem 119. White to play. This position often occurs in games and we are going to analyse it extensively. Where is the best place for White to invade ? ENDCOM W 1 R17 USER CORRECT ANSWER ENDUSER COM Correct Answer. If you want the corner, White 1 at the 3-3 point is the place to play. <= ENDCOM VAR W 1 M17 USER CORRECT ANSWER ENDUSER USER CORRECT ANSWER ENDUSER COM Correct Answer. Invading on the side with White 1 is also correct. <= ENDCOM ENDVAR EVENT BOARDSIZE 19 SETUP W L17 N16 P16 R16 B16 C14 C11 SETUP B C17 D16 F16 J17 N17 MARK 1@N16 COM Problem 120. Black to play. What does Black do when White attaches with 1 ? ENDCOM B 1 O16 USER CORRECT ANSWER ENDUSER COM Correct Answer. Wedging in with 1 is the correct move. ENDCOM VAR B 1 M16 COM Failure. Playing hane with 1 is a bad move. ENDCOM W 2 M17 B 3 O16 W 4 N15 B 5 P17 W 6 O15 B 7 O17 W 8 Q17 COM After White 8, the black stones are dead. <= ENDCOM ENDVAR W 2 O15 B 3 O17 W 4 M16 MARK 3@O17 COM After 3 and 4, ... ENDCOM B 5 R18 COM ... Black extends all the way to 5. <= ENDCOM EVENT BOARDSIZE 19 SETUP W F17 F16 K17 SETUP B D16 E17 D14 N17 Q16 R10 COM Problem 121. White to play. How should White invade the black position on the right side ? ENDCOM W 1 R16 MARK C@S15 B@R14 A@R17 USER CORRECT ANSWER ENDUSER COM Correct Answer. This time, instead of the 3-3 point at A, White should invade by attaching with 1. White could also invade at B or C. <= ENDCOM VAR W 1 R14 USER CORRECT ANSWER ENDUSER COM Correct Answer. Also correct. <= ENDCOM ENDVAR VAR W 1 S15 USER CORRECT ANSWER ENDUSER COM Correct Answer. Also correct. <= ENDCOM ENDVAR B 2 R17 W 3 R15 B 4 Q17 W 5 R12 B 6 P10 W 7 P12 COM The moves to 7 are joseki. White has succeeded in invading Black's moyo. <= ENDCOM EVENT BOARDSIZE 19 SETUP W C16 E16 H17 R17 R14 Q14 R11 C12 SETUP B K17 O16 Q16 Q17 R15 C10 MARK 1@Q17 COM Problem 122. White to play. Black 1 is a tight move. Where should White play next ? ENDCOM W 1 S15 USER CORRECT ANSWER ENDUSER COM Correct Answer. White should play 1. ENDCOM B 2 S16 VAR B 2 R16 COM Variation. Black could also play 2 ... ENDCOM W 3 S16 B 4 S17 MARK A@S18 COM ... and 4. The point A is left for the endgame. Both these variations are satisfactory for White. <= ENDCOM ENDVAR W 3 R16 B 4 S17 W 5 Q15 VAR W 5 R18 COM White 5 here would be disastrous for White. <= ENDCOM ENDVAR B 6 R18 COM The moves to 6 are a well-known joseki. <= ENDCOM EVENT BOARDSIZE 19 SETUP W B16 C14 C11 L17 M16 N16 O15 P16 R16 R17 SETUP B D16 C17 F16 J17 R18 O17 O16 N17 MARK 1@R17 COM Problem 123. Black to play. How does Black respond when White bumps into his stone with 1 ? ENDCOM B 1 P17 USER CORRECT ANSWER ENDUSER COM Correct Answer. Black 1 is the vital point. ENDCOM VAR B 1 Q18 COM Failure. Black can live by drawing back with 1, ... ENDCOM W 2 P17 B 3 P18 W 4 S18 B 5 M18 W 6 L18 B 7 O19 COM ... but he has a smaller life and doesn't leave weaknesses in White's position. <= ENDCOM ENDVAR W 2 S18 VAR W 2 Q18 COM If White 2 here, ... ENDCOM B 3 Q17 COM ... Black plays 3 and he can break through White's wall. <= ENDCOM ENDVAR B 3 L18 W 4 K18 B 5 M18 W 6 K17 B 7 Q18 MARK A@P15 COM Black lives with the moves to 7. Black now aims to cut at A. <= ENDCOM EVENT BOARDSIZE 19 SETUP W F17 F16 K17 R16 R15 SETUP B D16 E17 D14 N17 Q16 R17 S17 R10 MARK 4@S17 3@R15 2@R17 1@R16 COM Problem 124. White to play. In answer to White 3, Black descends to 4. How should White respond ? ENDCOM W 1 P14 USER CORRECT ANSWER ENDUSER COM Correct Answer. The knight move of White 1 makes good shape. ENDCOM B 2 P16 COM Defending with Black 2 is the proper move. ENDCOM W 3 R12 B 4 Q10 W 5 P12 MARK 3@R12 COM White can now complete her shape with 3 and 5. <= ENDCOM EVENT BOARDSIZE 19 SETUP W C12 C16 E16 H17 R17 R14 Q14 R11 SETUP B C10 K17 O16 Q16 R15 S15 MARK 1@S15 \t@R17 COM Problem 125. White to play. Black 1 is a strong response to the invasion by the marked stone. Black intends to give White the corner and attack the right side. What is White's next move ? ENDCOM W 1 P17 MARK A@P18 USER CORRECT ANSWER ENDUSER COM Correct Answer. Peeping at White 1 is a tesuji. As you will see in the Failure Diagram, White 1 at A is not good. <= ENDCOM VAR W 1 P18 COM Failure. ENDCOM B 2 P17 MARK 1@P18 COM Black 2 is a good response to White 1. ENDCOM W 3 O18 COM If White 3, ... ENDCOM VAR W 3 Q18 COM If White draws back to 3, ... ENDCOM B 4 O18 COM ... Black blocks at 4. ENDCOM W 5 S18 COM White gets a small life. White's result is bad. <= ENDCOM ENDVAR B 4 Q18 COM ... Black plays 4 and takes the corner. <= ENDCOM ENDVAR EVENT BOARDSIZE 19 SETUP W K17 Q17 Q15 S14 SETUP B D17 C14 H17 R13 R10 COM Problem 126. Black to play. This time the white enclosure is facing the other direction. Where should Black invade ? ENDCOM B 1 M17 USER CORRECT ANSWER ENDUSER COM Correct Answer. Invading at 1 is the vital point. ENDCOM W 2 L16 COM White 2 is the standard response. ENDCOM VAR W 2 O17 COM Variation. If White defends from the other side with 2, ... ENDCOM B 3 L16 COM ... Black attacks the lone white stone with 3. <= ENDCOM ENDVAR B 3 P17 COM Next, Black attaches at 3, and, ... ENDCOM VAR B 3 N15 MARK @@P17 COM Variation. Instead of @, playing directly at 3 is also possible. <= ENDCOM ENDVAR W 4 P16 B 5 O17 COM ... after 5, ... ENDCOM W 6 Q18 B 7 N15 COM ... jumps to 7. <= ENDCOM EVENT BOARDSIZE 19 SETUP W F17 F16 K17 R16 R15 Q14 P14 SETUP B D16 E17 D14 N17 Q16 Q15 R17 S17 R14 R10 MARK 3@R14 2@Q14 1@Q15 \t@P14 COM Problem 127. White to play. After White plays the marked stone, Black pushes down and cuts with 1 and 3. What should White do ? ENDCOM W 1 R13 USER CORRECT ANSWER ENDUSER COM Correct Answer. White should atari with 1, ... ENDCOM B 2 S14 W 3 P16 COM ... then attach at 3. ENDCOM B 4 Q17 VAR B 4 S15 MARK 3@P16 COM Failure. If Black ignores White 3 and immediately goes after the two white stones with 4, ... ENDCOM W 5 P15 B 6 Q17 W 7 P17 MARK 5@P16 COM ... White plays 5 and 7, isolating the black stone at the top. <= ENDCOM ENDVAR W 5 S13 B 6 S15 COM After Black 6, ... ENDCOM W 7 P12 COM ... White makes shape with 7. <= ENDCOM EVENT BOARDSIZE 19 SETUP W C16 E16 H17 C12 R17 P17 R14 Q14 R11 SETUP B K17 C10 P16 O16 Q16 R15 S15 MARK 1@P16 \t@P17 COM Problem 128. White to play. Connecting with Black 1 is an obvious move. In response, White has two possibilities. Where are they ? ENDCOM W 1 O17 MARK A@O18 USER CORRECT ANSWER ENDUSER COM Correct Answer. White can play either 1 or A. Both of these moves are joseki. <= ENDCOM VAR W 1 Q17 COM Failure. Connecting at 1 is heavy. ENDCOM B 2 O17 COM Black plays 2 and, ... ENDCOM W 3 O18 VAR W 3 S18 COM White 3 here is better, she just manages to live. <= ENDCOM ENDVAR B 4 N18 W 5 P19 MARK 3@O18 COM ... after 3 and 5, ... ENDCOM B 6 Q18 W 7 R18 B 8 T18 MARK 6@Q18 COM ... kills White with 6 and 8. <= ENDCOM ENDVAR VAR W 1 O18 USER CORRECT ANSWER ENDUSER COM Correct Answer. Also correct. <= ENDCOM ENDVAR EVENT BOARDSIZE 19 SETUP W C16 E16 K17 N17 R14 Q14 R10 P10 SETUP B P17 Q16 R15 C10 COM Problem 129. White to play. The shape of the black stones is called 'the three crows'. This is a very solid formation, but is still vulnerable to an invasion if White has built up strong positions in the vicinity. Where does White invade ? ENDCOM W 1 R17 USER CORRECT ANSWER ENDUSER COM Correct Answer. White 1 is the vital point. ENDCOM B 2 R16 COM Black 2 is the severest response. ENDCOM VAR B 2 S16 COM Variation. If Black 2 here, ... ENDCOM W 3 S17 B 4 S14 W 5 P18 B 6 O18 W 7 Q18 B 8 O17 W 9 N18 B 10 O19 W 11 S18 COM ... White easily lives with the moves to 11. <= ENDCOM ENDVAR W 3 Q18 B 4 P18 W 5 S18 B 6 S16 W 7 R19 B 8 S17 W 9 Q17 B 10 T18 COM After 10, ... ENDCOM W 11 P16 MARK A@S19 COM ... White cuts at 11, and the life or death of the stones in the corner depends on a ko starting at A. <= ENDCOM EVENT BOARDSIZE 19 SETUP W F17 F16 K17 R16 R15 P14 SETUP B D16 E17 D14 N17 Q16 R17 S17 R13 R10 MARK 1@R13 \t@P14 COM Problem 130. White to play. After White plays the marked stone, Black attacks with 1. How does White handle this move ? ENDCOM W 1 P16 USER CORRECT ANSWER ENDUSER COM Correct Answer. Attaching at 1 is the correct move. ENDCOM B 2 P17 VAR B 2 Q15 COM Variation. If Black tries to push through with 2, ... ENDCOM W 3 Q14 COM ... White stops him with 3. ENDCOM B 4 Q17 COM Black must connect with 4. ENDCOM W 5 R14 COM Next, White connects at 5. This result is not at all bad for her. <= ENDCOM ENDVAR W 3 Q15 B 4 Q17 W 5 N14 COM White makes sabaki with the moves to 5. <= ENDCOM EVENT BOARDSIZE 19 SETUP W C16 E16 H17 C12 R17 P17 O18 R14 Q14 R11 SETUP B K17 C10 O17 O16 P16 Q16 R15 S15 MARK 2@O17 1@O18 COM Problem 131. White to play. Against White 1, Black 2 is a strong move. How does White live ? ENDCOM W 1 P18 USER CORRECT ANSWER ENDUSER COM Correct Answer. Connecting at 1 is the proper move. ENDCOM VAR W 1 Q17 COM Failure. Connecting at 1 is bad. ENDCOM B 2 N18 W 3 P18 COM After White 3, ... ENDCOM VAR W 3 S18 COM If White 3 here, she lives, but ... ENDCOM B 4 P18 COM ... Black can capture a stone in sente with 4. <= ENDCOM ENDVAR B 4 T18 COM ... Black kills her with 4. <= ENDCOM ENDVAR B 2 N18 COM After Black blocks with 2, ... ENDCOM W 3 S18 COM White lives with 3. <= ENDCOM EVENT BOARDSIZE 19 SETUP W C16 E16 K17 N17 R17 R14 Q14 R10 P10 SETUP B P17 Q16 R15 S15 C10 MARK B@Q18 A@P18 1@R17 2@S15 COM Problem 132. White to play. In answer to White 1, Black 2 is also a strong move. If White next plays A, Black can make life with B. So how should White play ? ENDCOM W 1 Q17 USER CORRECT ANSWER ENDUSER COM Correct Answer. White plays 1, ... ENDCOM B 2 P16 COM ... forcing Black to connect at 2. ENDCOM VAR B 2 P18 COM Failure. Black 2 is an overplay. ENDCOM W 3 P16 COM White cuts with 3, and gets the advantage in the capturing race that follows. <= ENDCOM ENDVAR W 3 P18 COM Now White can hane at 3 ... ENDCOM B 4 O18 W 5 Q18 B 6 O17 W 7 S18 COM ... and live with the moves to 7. <= ENDCOM EVENT BOARDSIZE 19 SETUP W F17 F16 K17 R16 SETUP B D16 E17 D14 N17 Q16 R15 R10 MARK 1@R15 \t@R16 COM Problem 133. White to play. This time Black responds to the marked stone by blocking on the outside with 1. What is White's response here ? ENDCOM W 1 S15 USER CORRECT ANSWER ENDUSER COM Correct Answer. Playing hane underneath with 1 is the proper move. <= ENDCOM VAR W 1 R17 USER CORRECT ANSWER ENDUSER COM Correct Answer. It is also possible for White to play 1 here. <= ENDCOM ENDVAR EVENT BOARDSIZE 19 SETUP W C16 E16 H17 C12 O17 P17 Q18 R17 Q14 R14 R11 SETUP B C10 K17 N17 Q17 Q16 P16 O16 R15 S15 MARK 4@N17 3@Q18 2@Q17 1@O17 COM Problem 134. White to play. The moves from White 1 to Black 4 are a joseki. What is White's next move ? There are two correct answers. ENDCOM W 1 N18 USER CORRECT ANSWER ENDUSER COM Correct Answer. The hane of White 1 is the usual answer. ENDCOM VAR W 1 S18 USER CORRECT ANSWER ENDUSER COM Correct Answer. White could also live in the corner by playing 1. ENDCOM B 2 N18 COM The exchange of 2 ... ENDCOM W 3 P19 MARK A@N16 COM ... for 3 is important. After this, White will aim to cut at A. <= ENDCOM ENDVAR B 2 R18 COM Black cuts with 2 and ... ENDCOM W 3 P18 COM ... White connects with 3. ENDCOM B 4 S17 COM Next, Black will play 4, taking the corner, and ... ENDCOM W 5 M17 COM ... White will play 5. <= ENDCOM EVENT BOARDSIZE 19 SETUP W C16 E16 K17 N17 R14 Q14 P10 R10 R17 S17 SETUP B C10 P17 Q17 Q16 R15 S16 MARK D@S18 C@Q15 B@S15 A@R16 4@Q17 2@S16 3@S17 1@R17 COM Problem 135. White to play. The moves from White 1 to Black 4 have been played. White would like to play A - Black B - White C, but Black would then play a tesuji at D, capturing White's stones in the corner. How should White play ? ENDCOM W 1 S18 USER CORRECT ANSWER ENDUSER COM Correct Answer. White 1 is the vital point. ENDCOM B 2 S14 COM If Black defends his weakness by playing 2, ... ENDCOM VAR B 2 Q18 COM Failure. Black 2, trying to kill White, is a bad move. ENDCOM W 3 R16 COM White plays 3 and ... ENDCOM B 4 S15 W 5 Q15 COM ... cuts with 5, winning the capturing race in the corner by one move. <= ENDCOM ENDVAR W 3 Q18 B 4 P18 W 5 Q19 MARK 3@Q18 COM ... White lives in the corner with 3 and 5. <= ENDCOM EVENT BOARDSIZE 19 SETUP W K17 F16 F17 R16 S15 SETUP B D16 D14 E17 N17 Q16 R15 Q15 R10 MARK 2@Q15 1@S15 COM Problem 136. White to play. Black answers White 1 by connecting at 2. What is White's next move ? ENDCOM W 1 S16 USER CORRECT ANSWER ENDUSER COM Correct Answer. White 1 is the best move. ENDCOM VAR W 1 R17 USER CORRECT ANSWER ENDUSER COM Correct Answer. If White plays 1, ... ENDCOM B 2 S14 MARK 1@R17 COM ... Black blocks at 2. In certain positions, White 1 could be a good move. <= ENDCOM ENDVAR B 2 S14 COM If Black blocks with 2, ... ENDCOM W 3 Q17 B 4 P17 W 5 Q18 MARK 3@Q17 COM ... White lives in the corner with 3 and 5. <= ENDCOM EVENT BOARDSIZE 19 SETUP W C16 E16 H17 C12 R14 Q14 R11 R17 SETUP B K17 C10 O16 Q16 R15 S16 MARK 2@S16 1@R17 COM Problem 137. White to play. This time Black responds with the diagonal move of 2. What should White do in this case ? ENDCOM W 1 P18 USER CORRECT ANSWER ENDUSER COM Correct Answer. In this case, the knight move of White 1 is the only way. This move was criticised in Problem 125, but in this case it is good. <= ENDCOM VAR W 1 P17 COM Failure. If White plays 1 ... ENDCOM B 2 P16 W 3 O18 COM ... and 3, ... ENDCOM B 4 Q17 W 5 Q18 B 6 O17 W 7 P18 B 8 S18 COM ... the sequence continues up to 8. ENDCOM W 9 R18 COM If White connects at 9, ... ENDCOM VAR W 9 M17 COM If White 9 here, ... ENDCOM B 10 R18 COM ... Black takes the corner with 10. Either way, Black ends up with a thick position. <= ENDCOM ENDVAR B 10 S14 COM ... Black plays 10. <= ENDCOM ENDVAR EVENT BOARDSIZE 19 SETUP W C16 E16 H17 C12 R14 Q14 R11 R17 SETUP B K17 C10 O16 Q16 R16 R15 MARK 2@R16 1@R17 COM Problem 138. White to play. How does White respond to Black 2 ? ENDCOM W 1 Q18 USER CORRECT ANSWER ENDUSER COM Correct Answer. The diagonal move of 1 gives White good shape. ENDCOM VAR W 1 Q17 COM Failure. White 1 is a bad move. ENDCOM B 2 P17 COM Black plays 2 and gets a solid shape. ENDCOM W 3 S16 COM After this, White must play 3, ... ENDCOM B 4 S15 W 5 S18 B 6 T16 W 7 T17 COM ... and she can only live in the corner by winning a ko. <= ENDCOM ENDVAR B 2 Q17 COM If Black 2, ... ENDCOM W 3 S18 COM ... White plays 3, easily making life in the corner. <= ENDCOM EVENT BOARDSIZE 19 SETUP W F17 F16 K17 R16 S16 S15 SETUP B E17 D16 D14 N17 R17 Q16 Q15 R15 R10 MARK 1@R17 COM Problem 139. White to play. How does White respond to Black 1 ? ENDCOM W 1 S17 USER CORRECT ANSWER ENDUSER COM Correct Answer. White first forces with 1, ... ENDCOM VAR W 1 R13 COM Failure. Jumping to 1 first allows Black ... ENDCOM B 2 S17 MARK A@S14 COM ... to block with 2 in sente, he now threatens to play A. This is a setback for White. <= ENDCOM ENDVAR B 2 R18 W 3 R13 COM ... then jumps lightly to 3. <= ENDCOM EVENT BOARDSIZE 19 SETUP W C16 E16 C12 H17 R17 P18 Q14 R14 R11 SETUP B C10 K17 O16 Q16 R15 S16 P17 MARK 1@P17 COM Problem 140.White to play. How does White respond to Black 1 ? ENDCOM W 1 S17 MARK A@R16 USER CORRECT ANSWER ENDUSER COM Correct Answer. White 1 aims at A, ... ENDCOM B 2 S14 COM ... so Black must defend with 2. ENDCOM VAR B 2 Q18 COM Failure. Black 2 is unreasonable. ENDCOM W 3 R16 B 4 S15 W 5 Q15 MARK 3@R16 COM White pushes through with 3 and 5, winning three black stones in a capturing race. <= ENDCOM ENDVAR W 3 O18 COM Next White extends to 3, ending the sequence in good shape. <= ENDCOM EVENT BOARDSIZE 19 SETUP W G17 M17 K16 O18 R14 Q14 R10 SETUP B D16 E17 C14 O16 Q16 Q18 R15 COM Problem 141. White to play. How does White invade the corner ? ENDCOM W 1 P17 USER CORRECT ANSWER ENDUSER COM Correct Answer. White first peeps at 1. ENDCOM B 2 P16 COM Black must defend at 2 to avoid being confined to the corner. ENDCOM W 3 R17 COM White then invades at 3. ENDCOM B 4 Q17 W 5 S15 B 6 S16 W 7 R16 B 8 S17 W 9 Q15 B 10 R18 MARK 3@R17 COM After White 3, the moves to Black 10 are inevitable. White is satisfied because her stones on the right have become strong. <= ENDCOM EVENT BOARDSIZE 19 SETUP W F17 F16 K17 R16 S16 S15 SETUP B D16 E17 D14 N17 Q16 R17 S17 R15 R10 MARK 2@S16 3@S17 1@R17 \t@S15 COM Problem 142. White to play. Black takes the corner with 1 and 3. What should White do ? ENDCOM W 1 Q15 USER CORRECT ANSWER ENDUSER COM Correct Answer. White should cut with 1, ... ENDCOM B 2 R14 W 3 Q17 COM ... then atari with 3. ENDCOM B 4 P16 W 5 S14 B 6 P17 COM After Black takes the corner with 6, ... ENDCOM VAR B 6 R13 COM Variation. Black extends to 6, aiming to get thickness in the center. ENDCOM W 7 Q18 COM However, White takes the corner with 7. <= ENDCOM ENDVAR W 7 R13 B 8 Q14 W 9 P13 MARK 7@R13 COM ... White makes sabaki with 7 and 9. <= ENDCOM EVENT BOARDSIZE 19 SETUP W D18 F17 H17 K17 R14 Q14 R10 SETUP B C17 D16 D14 M17 O16 Q16 R15 COM Problem 143. White to play. Black's position here is much tighter. Where should White invade ? ENDCOM W 1 O18 USER CORRECT ANSWER ENDUSER COM Correct Answer. Invading with 1 is a good move. ENDCOM VAR W 1 R17 USER CORRECT ANSWER ENDUSER COM Correct Answer. A direct invasion here is also possible. <= ENDCOM ENDVAR B 2 Q18 COM If Black defends the corner with 2, ... ENDCOM VAR B 2 N17 COM Variation. If Black prevents White from linking up on the left by playing 2, ... ENDCOM W 3 R17 MARK 2@N17 1@O18 COM ... White plays on the 3-3 point with 3. With the exchange of 1 for 2 in place, this is an effective move. <= ENDCOM ENDVAR W 3 N17 B 4 N16 W 5 M18 MARK 3@N17 COM ... White links up with 3 and 5. <= ENDCOM EVENT BOARDSIZE 19 SETUP W Q16 R13 M17 SETUP B D16 G17 Q10 COM Problem 144. Black to play. The white formation is called 'kannon-biraki' in Japanese, meaning double-hinged doors. Such formations are defective and need an additional move to complete the territory they map out. Where should Black invade ? ENDCOM B 1 R17 USER CORRECT ANSWER ENDUSER COM Correct Answer. When faced with this formation, invading at the 3-3 point and living in the corner with Black 1 is the biggest move. ENDCOM VAR B 1 Q17 COM Failure. Attaching with 1 is not good. ENDCOM W 2 R17 B 3 P17 W 4 R18 MARK A@J17 3@P17 1@Q17 2@R17 COM White takes the corner with 2 and 4, leaving Black's stones 1 and 3 heavy. White can still settle her stone at the top by extending to A. <= ENDCOM ENDVAR W 2 Q17 COM Of course, White blocks from the wider side with 2. ENDCOM B 3 R16 W 4 R15 B 5 S15 W 6 S14 MARK 4@R15 COM White 4 and 6 are the strongest moves, but ... ENDCOM B 7 Q15 W 8 R14 B 9 Q18 W 10 P18 B 11 S18 W 12 Q19 B 13 R18 W 14 O17 B 15 S16 COM ... Black gets six points of territory after he connects with 15. <= ENDCOM EVENT BOARDSIZE 19 SETUP W D18 F17 H16 K16 M17 R14 Q14 R11 SETUP B C17 D16 C14 N18 O16 Q16 R15 MARK \t@N18 COM Problem 145. White to play. The marked black stone does not adequately protect the corner. White still has a way to invade. ENDCOM W 1 R17 USER CORRECT ANSWER ENDUSER COM Correct Answer. First White invades at the 3-3 point, ... ENDCOM B 2 S15 VAR B 2 Q17 COM Variation. If Black 2 here, ... ENDCOM W 3 S15 COM ... White hanes at 3. <= ENDCOM ENDVAR VAR B 2 R16 W 3 P18 B 4 N17 W 5 Q17 B 6 P17 W 7 S18 ENDVAR W 3 P18 COM ... then slides to 3, threatening to link up to the white stones on the left. ENDCOM B 4 N17 COM When Black defends at 4, ... ENDCOM W 5 S18 COM ... White lives with 5. <= ENDCOM EVENT BOARDSIZE 19 SETUP W D18 F17 H16 K17 R17 Q14 R14 R10 SETUP B C17 D16 D14 C10 M17 O16 Q16 R15 S15 MARK 2@S15 1@R17 COM Problem 146. White to play. When White invades at the 3-3 point, Black defends with 2. How does White continue ? ENDCOM W 1 P17 USER CORRECT ANSWER ENDUSER COM Correct Answer. White peeps with 1 and, ... ENDCOM B 2 P16 COM ... after Black connects with 2, ... ENDCOM W 3 O17 COM ... crawls to 3. ENDCOM VAR W 3 Q17 COM Variation. White could also live in the corner with 3 ... ENDCOM B 4 O17 W 5 S18 COM ... and 5. She has more territory, but ends in gote. <= ENDCOM ENDVAR B 4 Q17 W 5 Q18 B 6 R18 W 7 S18 B 8 P18 W 9 R19 COM Up to 9, White lives ... ENDCOM B 10 O18 COM ... in sente. <= ENDCOM EVENT BOARDSIZE 19 SETUP W M17 Q16 Q17 P18 Q19 S16 R15 R13 S14 R14 SETUP B D16 G17 Q18 R18 S18 R17 R16 S15 Q15 Q10 MARK 1@S16 COM Problem 147. Black to play. Instead of playing 14 in Problem 144, White tries to take away Black's eyes in the corner with 1. How should Black respond ? ENDCOM B 1 P17 USER CORRECT ANSWER ENDUSER COM Correct Answer. Black ataris with 1. ENDCOM W 2 P16 COM White has no choice but to play 2, but ... ENDCOM B 3 O17 MARK B@O16 A@O18 COM ... after Black 3, the points A and B become miai. Either way, Black will live. <= ENDCOM EVENT BOARDSIZE 19 SETUP W D18 F17 H16 K16 M17 R14 Q14 Q10 SETUP B C17 D16 C14 O17 O16 Q16 R15 COM Problem 148. White to play. Black's formation is very tight. Is it possible for White to invade here ? ENDCOM W 1 R17 USER CORRECT ANSWER ENDUSER COM Correct Answer. White's invasion at 1 is unreasonable. ENDCOM B 2 S15 COM Black blocks at 2 and ... ENDCOM W 3 P18 B 4 O18 W 5 P17 VAR W 5 Q18 COM Variation. If White draws back with 5, ... ENDCOM B 6 T18 COM ... Black's killing move is at 6. From this diagram it is easy to see just how big Black's territory is. <= ENDCOM ENDVAR B 6 P16 W 7 S18 B 8 P19 W 9 Q18 B 10 T17 COM ... after Black 10 it is clear that White is dead. <= ENDCOM EVENT BOARDSIZE 19 SETUP W B16 C14 C11 J17 M17 R14 R11 SETUP B C17 D16 F17 O17 Q16 S16 COM Problem 149. White to play. Here is another tight black formation. Can White invade Black's corner and live ? ENDCOM W 1 R17 USER CORRECT ANSWER ENDUSER COM Correct Answer. The moves from White 1 ... ENDCOM VAR W 1 S15 COM Alternative. Since White is unable to invade Black's corner, she should make this area as small as possible ... ENDCOM B 2 R17 W 3 O18 B 4 P18 W 5 O16 MARK 1@S15 3@O18 COM ... by playing the forcing moves of 1, 3, and 5. <= ENDCOM B 6 P17 ENDVAR B 2 R16 W 3 P18 B 4 O18 W 5 P17 B 6 P16 W 7 S17 COM ... to 7 are all good, but Black is too strong here and ... ENDCOM B 8 Q17 W 9 Q18 B 10 S18 COM ... White has no answer to Black 10. <= ENDCOM EVENT BOARDSIZE 19 SETUP W D16 D13 C6 D4 K4 O3 O5 O2 SETUP B O7 P3 Q4 Q6 R10 R16 P17 F17 J16 MARK 2@O2 1@P3 3@O7 COM Problem 150. White to play. Black maps out a huge moyo with 1 and 3. It is now urgent that White reduces the size of this moyo. Where is the weak point of Black's formation ? ENDCOM W 1 P15 MARK B@Q16 A@O17 USER CORRECT ANSWER ENDUSER COM Correct Answer. When Black has a tight small-knight enclosure with extensions on both sides, the weak point is White 1. Depending on how Black answers, White will make sabaki by playing at A of B. <= ENDCOM VAR W 1 O16 COM Not applicable here. White plays 1 when she wants to erase the top. ENDCOM B 2 O17 COM In this case, Black would push with 2, ... ENDCOM W 3 M16 B 4 O14 MARK 1@O16 COM ... then cap with 4. This move is very severe, since it not only attacks White's two stones, but also expands Black's moyo on the right. Clearly, White 1 is not a good idea in this position. <= ENDCOM ENDVAR VAR W 1 R12 COM The worst move. Invading with 1 gibes Black a target to attack. ENDCOM B 2 R14 COM Black first pincers with 2, ... ENDCOM W 3 P12 B 4 N12 COM ... then caps with 4. Black is strong above and below, so it will be hard for White to escape. <= ENDCOM ENDVAR VAR W 1 R15 COM A heavy shape. If White plays 1 ... ENDCOM B 2 Q15 W 3 R14 MARK 2@Q15 COM ... and 3, she is left with a heavy shape ... ENDCOM B 4 S16 MARK \t@R10 2@Q15 COM ... after Black 2 and 4. White cannot make a full extension down the side because of the presence of the marked stone. This is a terrible result for White. <= ENDCOM ENDVAR VAR W 1 D17 COM An iron rule. Locally, White 1 is a good move, but ... ENDCOM B 2 P15 COM ... Black then eliminates the weak point of his moyo by jumping to 2. When dealing with a moyo, the iron rule is 'Never let your opponent perfect his moyo.' <= ENDCOM ENDVAR EVENT BOARDSIZE 19 SETUP W C17 D10 D4 F3 K16 O17 SETUP B Q16 Q14 Q9 Q5 Q3 K4 COM Problem 151. Black to play. The black and white moyos divide the board. With one move, however, Black can break up White's moyo and wipe out much of it's influence. ENDCOM B 1 D16 MARK B@C16 A@D17 USER CORRECT ANSWER ENDUSER COM Correct Answer. Making a large-scale moyo from the 3-3 point is unnatural because Black will land a devastating blow in the center of White's position with 1. White will respond with A or B. ENDCOM VAR B 1 E17 COM Black is under attack. Playing one line deeper with 1 is bad ... ENDCOM W 2 D15 COM ... because Black will come under a severe attack with 2 ... ENDCOM B 3 H17 W 4 K17 COM ... and 4. <= ENDCOM ENDVAR VAR B 1 E16 COM Failure. If Black 1 here, ... ENDCOM W 2 D15 COM ... White 2 is again the vital point. <= ENDCOM ENDVAR W 2 C16 B 3 D15 W 4 E18 B 5 C15 COM After the moves to 5, Black's stones are quite resilient and cannot be easily attacked. ENDCOM W 6 F16 COM If White 6, ... ENDCOM B 7 F15 COM ... Black attaches at 7. <= ENDCOM EVENT BOARDSIZE 19 SETUP W D16 D13 C6 D4 K4 O3 O2 O5 P15 SETUP B O7 Q6 Q4 P3 R10 Q14 R16 P17 J16 F17 MARK 2@Q14 1@P15 COM Problem 152. White to play. Black 2 is the usual answer to the capping move of White 1. White's next move in common sense, but there are many variations you must consider. ENDCOM W 1 O17 USER CORRECT ANSWER ENDUSER COM Correct Answer. White should attach ... ENDCOM B 2 O18 VAR B 2 P16 COM Don't be afraid if Black pushes up ... ENDCOM W 3 O16 B 4 O15 MARK 2@P16 COM ... and cuts with 2 and 4. ENDCOM W 5 N15 B 6 O14 W 7 M16 MARK \t@P15 5@N15 COM White makes sabaki with 5 and 7, fully using the marked stone. <= ENDCOM ENDVAR VAR B 2 Q17 COM Drawing back with 2 is a quiet move. ENDCOM W 3 N15 MARK A@L17 COM However, after 3, White is satisfied because she has erased Black's moyo. Moreover, White can still aim at the extension of A. <= ENDCOM ENDVAR VAR B 2 O16 COM If the ladder favours Black, ... ENDCOM W 3 P16 B 4 Q17 MARK 2@O16 COM ... 2 and 4 are strong moves. ENDCOM W 5 N17 COM White would have to extend to 5 and ... ENDCOM B 6 N16 MARK 5@N17 2@O16 COM ... Black would push along at 6. White's position is not good. However, the ladder favours White here, so she would play 5 at 6 and capture the stone at 2. <= ENDCOM ENDVAR W 3 P18 MARK 1@O17 COM ... and cut with 1 and 3. ENDCOM B 4 Q18 VAR B 4 O16 COM Big profit. If Black is determined to get outside influence, the can play 4 ... ENDCOM W 5 N17 B 6 P16 COM ... and 6. ENDCOM W 7 Q18 COM White gets a big profit at the top. This is not a good result for Black. <= ENDCOM ENDVAR W 5 P16 B 6 P19 COM If Black captures with 6, ... ENDCOM VAR B 6 Q17 MARK \t@P16 COM Black connects. If Black connects with 6 in answer to the marked stone, ... ENDCOM W 7 N18 COM ... White ataris with 7. ENDCOM B 8 P19 COM This is a good result for White, but she must be careful where she makes her next move. <= ENDCOM ENDVAR W 7 Q17 COM ... White ataris with 7 and, ... ENDCOM B 8 P18 COM ... after Black connects at 8, ... ENDCOM W 9 N17 COM ... extends to 9. ENDCOM B 10 Q16 COM Black defends with 10 and ... ENDCOM VAR B 10 N15 COM The vital point, but ... Before defending on the right, Black could play on the vital point with 10. ENDCOM W 11 M15 B 12 N14 W 13 N16 MARK 11@M15 COM After White 11 and 13, ... ENDCOM B 14 Q16 MARK B@S18 A@R17 COM ... Black must go back and defend with 14. This result is better for White than the on in the Correct Answer. If Black omits 14, the aji of White A - Black 14 - White B remains. <= ENDCOM W 15 M14 ENDVAR W 11 N15 COM ... White makes good shape with 11. This is a middle-game joseki. <= ENDCOM EVENT BOARDSIZE 19 SETUP W C17 D14 D3 D2 E2 F2 F3 G4 H3 D7 C8 E7 C6 C5 C4 Q18 O17 L17 SETUP B G3 E3 E4 F4 D4 D5 D6 C7 B7 B4 B3 C3 O3 Q4 R5 Q16 R17 R14 MARK 1@D14 COM Problem 153. Black to play. White makes a large moyo with 1. Black has taken a lot of territory in the three corners, so all he needs to do is to break up this moyo. Should Black play a light erasing move or attack at the base of White's moyo ? ENDCOM B 1 K16 USER CORRECT ANSWER ENDUSER COM Correct Answer. Erase with a shoulder hit. Black is sated with solid territory, so he doesn't need to fight for more. It is sufficient just to erase White's moyo with the shoulder hit of 1. Remember the proverb: 'When you want to erase, hit at the shoulder !' ENDCOM VAR B 1 D17 COM The attachment doesn't work. Attaching at 1 might also be considered. ENDCOM W 2 D16 B 3 E16 COM Black hopes to make sabaki with 3, but ... ENDCOM VAR B 3 E17 COM Black's stones are heavy. Drawing back with 3 is also bad. ENDCOM W 4 C18 B 5 E16 W 6 D15 B 7 J17 COM After 7, ... ENDCOM W 8 G17 COM ... White invades at 8, and ... ENDCOM B 9 G16 W 10 H17 B 11 H16 W 12 J18 B 13 J16 W 14 K17 COM ... the black stones are again heavy after the moves to 14. There is a proverb that says, 'when you want to make sabaki, attach !' In this case, the proverb does not apply. <= ENDCOM ENDVAR W 4 E17 B 5 D18 W 6 E18 B 7 D15 W 8 C16 B 9 F16 W 10 C15 B 11 F18 W 12 C18 B 13 F17 W 14 D19 MARK \t@L17 COM ... up to 14, Black's stones have no eyes and are blocked from extending by the marked stone. These4 stones have become a burden on Black. <= ENDCOM ENDVAR VAR B 1 J17 COM An ideal result for White. If Black invades at 1, ... ENDCOM W 2 G17 COM ... White will attach with 2. ENDCOM B 3 J15 COM All Black can do is to run away into the center with 3, ... ENDCOM W 4 L15 COM ... but White continues the chase with 4. By attacking theses black stones, White will be able to make territory. This is an ideal result for White. <= ENDCOM ENDVAR VAR B 1 Q10 MARK \t@R14 \t@R5 COM Good shape, but ... Black 1 is a slow and deliberate way of playing and makes an ideal shape with Black's two marked stones. ENDCOM W 2 H16 MARK A@K16 COM On the other hand, White 2 is also a good point, The result here must be considered even. Clearly, it is better to disrupt White's moyo by playing the moves beginning with the shoulder hit at A. <= ENDCOM ENDVAR W 2 K17 VAR W 2 L16 COM A successful erasure. White could also push up with 2 ... ENDCOM B 3 K15 W 4 L15 COM ... and 4, ... ENDCOM B 5 K14 W 6 J18 COM ... then slide to 6. ENDCOM B 7 L14 COM But 7 is a thick move, giving Black influence throughout the board. Black has successfully erased White's moyo and his three corners are still intact. <= ENDCOM ENDVAR B 3 J16 W 4 L16 B 5 K14 W 6 L15 B 7 H13 MARK A@M13 COM The moves to 7 are joseki. After this, White will aim to play at A to set up a base from which to attack the right side and the top right corner. <= ENDCOM EVENT BOARDSIZE 19 SETUP W D16 D13 C6 D4 K4 O5 O3 O2 N18 O17 P16 P15 SETUP B P3 Q4 Q6 O7 R10 F17 J16 R16 P17 Q14 Q17 Q18 P19 O18 MARK 4@P19 2@Q17 3@N18 1@P16 \t@P18 COM Problem 154. White to play. The white stone that has been at the marked point has been working overtime: White has been able to make two ataris pivoting on this stone. However, the next move is the really important one and, if White misses it, all her good work could go to waste. ENDCOM W 1 M15 USER CORRECT ANSWER ENDUSER COM Correct Answer. When you are trying to make sabaki, you must play lightly. White 1 makes a resilient shape. This is a beautiful move. ENDCOM VAR W 1 N16 COM Failure. White 1 may look like an efficient move, since it protects all the cutting points, but ... ENDCOM B 2 M17 COM ... it results in a heavy shape after Black peeps at 2. ENDCOM W 3 N17 COM Because White has tried to save all of her stones, they will all come under attack. <= ENDCOM ENDVAR B 2 N17 COM There is nothing to worry about if Black cuts at 2. ENDCOM W 3 M17 MARK \t@O17 COM Just atari at 3 and sacrifice the marked stone. ENDCOM B 4 O16 COM After Black captures with 4, ... ENDCOM W 5 O15 COM ... White plays 5 and all of her stones are working efficiently. When you are trying to make sabaki, you have no responsibility to save all your stones. All you want to do is to establish a viable presence in the area you are fighting. <= ENDCOM EVENT BOARDSIZE 19 SETUP W D16 C14 C3 B6 C5 D5 E6 D7 E4 E3 H4 Q18 O17 L17 K17 L16 L15 SETUP B B3 A4 B5 C4 D4 D3 D2 D6 K4 Q5 Q3 Q9 Q14 Q16 R17 K16 J16 K14 MARK 6@L15 4@L16 2@K17 5@K14 3@J16 1@K16 COM Problem 155. Black to play. Black has reduced White's moyo with the moves 1 to 5. Taking the overall position into account, how should Black answer White 6 ? ENDCOM B 1 L14 USER CORRECT ANSWER ENDUSER COM Correct Answer. Black should block at 1. ENDCOM VAR B 1 H13 COM Failure. If Black blindly plays the joseki move of 1, ... ENDCOM W 2 M13 COM ... White jumps out to 2, erasing Black's moyo. Since Black's moyo is bigger than White's, the exchange favours White. <= ENDCOM ENDVAR W 2 K15 COM If White pushes through with 2 ... ENDCOM VAR W 2 R4 MARK 1@L14 COM The actual game. This position was taken from the second game of the 3rd Kisei title match, played between Fujisawa Shuko (White) and Ishida Yoshio. When Ishida played 1, Fujisawa probed with 2, ... ENDCOM B 3 Q4 W 4 L7 COM ... then jumped to 4, thereby avoiding the unfavourable result in the Correct Answer. <= ENDCOM ENDVAR B 3 J14 W 4 J15 COM ... and 4, ... ENDCOM B 5 H14 MARK A@C17 COM ... Black builds a huge moyo in the center of the board. Black is now aiming at the invasion of A. <= ENDCOM EVENT BOARDSIZE 19 SETUP W D16 D13 C6 D4 K4 O5 O3 O2 P15 SETUP B P3 Q4 Q6 O7 R10 R16 P17 O16 J16 F17 MARK 2@O16 1@P15 COM Problem 156. White to play. When Black considers the top important, he will play 2. In that case, White will focus her attention on the right. Try to think a few moves ahead and give White a shape that is not heavy. ENDCOM W 1 Q16 USER CORRECT ANSWER ENDUSER COM Correct Answer. White must first play 1, ... ENDCOM VAR W 1 R15 MARK @@Q16 COM Failure. If you immediately attach with 1, neglecting to first play at @, ... ENDCOM B 2 Q16 COM ... Black will play 2 himself, ... ENDCOM W 3 Q15 B 4 N14 COM ... then jump out into the center with 4. White's three stones are heavy and almost without hope. <= ENDCOM ENDVAR B 2 Q17 W 3 R15 COM ... then 3. ENDCOM B 4 S16 W 5 Q11 VAR W 5 R12 COM Failure. White 5 is heavy. ENDCOM B 6 P11 MARK \t@S16 COM Black launches an attach with 2 and this stone, in concert with the marked stone, will make it hard for White to get sabaki. <= ENDCOM ENDVAR B 6 R11 W 7 Q12 B 8 Q10 W 9 O11 B 10 P10 W 11 N14 MARK A@R3 COM Up to 11, White makes a fine sabaki. Black has solidified his lower right side, but there still remains a white invasion at A. <= ENDCOM EVENT BOARDSIZE 19 SETUP W D17 C15 C12 K17 N17 P17 SETUP B C10 R17 R14 COM Problem 157. Black to play. What is the best way to reduce White's moyo on the upper right ? Is a deep or shallow invasion called for ? ENDCOM B 1 J16 USER CORRECT ANSWER ENDUSER COM Correct Answer. The shoulder hit of Black 1 is the best move. A deeper invasion would be dangerous. ENDCOM VAR B 1 J15 COM Failure. Erasing White's moyo with Black 1 ... ENDCOM W 2 H16 COM ... induces White to play 2, which is ideally placed in relation to her other stones. <= ENDCOM ENDVAR VAR B 1 E15 COM Failure. Capping with Black 1 is also dubious. ENDCOM W 2 F16 COM Again, White 2 is an ideal point. <= ENDCOM ENDVAR VAR B 1 H17 COM Failure. Because White's three stones at the top right are so strong, invading at Black 1 is foolish. ENDCOM W 2 F17 COM White attacks with 2 ... ENDCOM B 3 H15 W 4 K15 COM ... and 4, and all Black can do is escape with this stones. <= ENDCOM ENDVAR W 2 J17 VAR W 2 K16 COM Variation. White could also push up with 2, ... ENDCOM B 3 J15 W 4 H18 COM ... then slide to 4. ENDCOM VAR W 4 K15 COM If White 4 here, ... ENDCOM B 5 J14 COM ... Black would play at 5. <= ENDCOM ENDVAR B 5 K15 COM White gets profit, while Black gets influence. <= ENDCOM ENDVAR B 3 H16 W 4 L15 B 5 J13 COM After Black jumps out to 5, he has nothing to worry about. One thing you must remember when you make a shoulder hit: expect to end in gote. <= ENDCOM EVENT BOARDSIZE 19 SETUP W D16 D13 C6 D4 K4 O5 O3 O2 P15 SETUP B P3 Q4 Q6 O7 R10 P17 R16 Q15 J16 F17 MARK 2@Q15 1@P15 COM Problem 158. White to play. The attachment of Black 2 is a move used in special situations. It is a move contrary to the go principle of not attaching against attacking stones. But in this case, Black's corner is strong and he is not worried about eyes. Try to read five moves ahead. ENDCOM W 1 P16 USER CORRECT ANSWER ENDUSER COM Correct Answer. By bumping against Black with 1, White is looking for a way to make shape. ENDCOM B 2 O17 COM Black 2 is absolutely necessary. ENDCOM W 3 Q14 COM After that, White 3 ... ENDCOM B 4 Q16 W 5 O13 COM ... and 5 make good shape. <= ENDCOM VAR W 5 P13 COM Failure. White 5 here would create a heavy shape. <= ENDCOM ENDVAR EVENT BOARDSIZE 19 SETUP W D17 C15 C12 K16 N17 SETUP B C10 Q17 R15 COM Problem 159. Black to play. The position is similar to the one in Problem 157. However, there are some differences. These differences should influence the way you erase White's moyo. ENDCOM B 1 H17 MARK B@H15 A@K18 \t@K16 USER CORRECT ANSWER ENDUSER COM Correct Answer. Since the marked stone is on the fourth line, light erasing moves such as caps or shoulder hits are not applicable. Black 1 is the perfect point because it aims at White's weak underbelly at A or a jump at B. ENDCOM VAR B 1 H16 COM Failure. Playing on the fourth line with 1 is bad. ENDCOM W 2 F17 COM White extends to 2 and Black's stone is without roots or follow-up moves. <= ENDCOM ENDVAR VAR B 1 H15 COM Failure. Erasing lightly with Black 1 is a failure. ENDCOM W 2 H17 COM White answers with 2, taking profit. <= ENDCOM ENDVAR W 2 H15 COM That is, if White caps at 2, ... ENDCOM VAR W 2 J17 COM Variation. White might attach at 2. ENDCOM B 3 H15 COM In this case, Black jumps lightly to 3, escaping into the center. ENDCOM VAR B 3 E17 COM However, Black can prevent White from linking up by exchanging 3 ... ENDCOM W 4 D16 COM ... for 4, ... ENDCOM B 5 H15 COM ... then jumping to 5. ENDCOM W 6 H18 COM If White now plays 6, ... ENDCOM B 7 G17 COM ... she can't link up after 7. <= ENDCOM ENDVAR W 4 H18 B 5 G17 W 6 G18 MARK 4@H18 COM Linking up to her stones at the top with 4 and 6 are big moves, but since White was strong here to begin with, this was to be expected. <= ENDCOM ENDVAR B 3 K18 W 4 L17 VAR W 4 F17 COM If White 4 here, ... ENDCOM B 5 L17 MARK 1@H17 COM ... Black answers at 5. In any case, as long as there is room to expand, a deep invasion at 1 is possible. <= ENDCOM ENDVAR B 5 F17 MARK 3@K18 COM ... Black plays 3 and 5, taking profit while making a stable position. <= ENDCOM EVENT BOARDSIZE 19 SETUP W D4 F4 P3 R4 R18 R17 Q16 Q15 P17 P14 SETUP B D17 C15 D10 C6 Q13 Q14 R12 R15 R16 S17 L17 COM Problem 160. Black to play. There are a lot of point where you can invade, but any invasion you make should take into account White's thickness on the right. ENDCOM W 1 H16 MARK A@H18 USER CORRECT ANSWER ENDUSER COM Correct Answer. Playing on the fourth line with White 1 is the best move. With a high move, escaping will be easy. For Black to try to link up at A would be submissive, so it is out of the question. ENDCOM VAR W 1 J17 COM Failure. A deep invasion with White 1 is dubious. ENDCOM B 2 J15 VAR B 2 G17 MARK 1@J17 COM Variation. Another way for Black to refute White 1 is to play 2 in response. This is a good move because it is in the right direction from the corner enclosure. <= ENDCOM ENDVAR W 3 K16 B 4 O16 MARK 2@J15 COM After Black 2 and 4, which hit White at her vital points, you will probably agree that the momentum of the game is in Black's favour. ENDCOM W 5 O15 MARK 4@O16 COM For example, if White answers 4 with 5, ... ENDCOM B 6 O17 W 7 P18 B 8 N15 COM ... the sequence will continue up to 8. Black clearly has the advantage. <= ENDCOM ENDVAR VAR W 1 E15 COM Failure. White 1 here is also a bad move, ... ENDCOM B 2 F16 COM ... because Black can answer with the knight move at 2, eliminating his thinness on the upper side. <= ENDCOM ENDVAR B 2 L15 COM Black's best course is to jump out with 2. ENDCOM VAR B 2 H14 COM Variation. Black might cap with 2 intending to build a moyo at the top. ENDCOM W 3 K16 COM However, White replies with the shoulder hit at 3 and ... ENDCOM B 4 L16 W 5 K15 B 6 L15 W 7 K14 B 8 M13 W 9 K12 MARK 2@H14 8@M13 6@L15 4@L16 COM ... escapes into the center with the moves to 9. Black's wall of 4, 6, and 8 is now neutralised by White's wall on the right and, with White's thickness in the center, Black 2 has failed to increase the size of his moyo on the left. <= ENDCOM ENDVAR W 3 H14 COM However, White also jumps into the center with 3 ... ENDCOM B 4 L13 W 5 H12 COM ... and 5, and Black's moyo is erased. <= ENDCOM EVENT BOARDSIZE 19 SETUP W D5 C4 D3 D2 Q9 P6 Q6 Q5 Q4 P3 R3 R2 R15 Q15 Q13 P13 Q17 F17 J17 SETUP B C17 D16 D14 C10 C7 E3 E4 G4 L3 S3 R4 R5 Q7 R8 R9 Q12 R13 R14 COM Problem 161. Black to play. In this game, White has built up a moyo at the top. How should Black erase it ? ENDCOM B 1 K16 USER CORRECT ANSWER ENDUSER COM Correct Answer. When you look at the thickness on the right, a light erasing move is what comes in your mind. The shoulder hit of Black 1 is the best move. If you play any deeper, your stone will meet with a severe counterattack, so you cannot expect to reduce White's territory any more than this. ENDCOM VAR B 1 K15 COM Failure. A light erasing move such as Black 1 is inadequate. ENDCOM W 2 L16 COM White is satisfied with the territory she gets after playing 2. <= ENDCOM ENDVAR VAR B 1 L17 COM Failure. If you think of a deep invasion, Black 1 is the move, but ... ENDCOM W 2 K16 MARK A@K15 COM ... after White 2 or A, Black will come under a severe attack. Black will have to put all his energy into making life on the right. <= ENDCOM ENDVAR W 2 K17 COM White answers with 2, ... ENDCOM B 3 L16 W 4 J16 B 5 K14 W 6 J15 B 7 M13 COM ... and the joseki to Black 7 follows. <= ENDCOM EVENT BOARDSIZE 19 SETUP W D16 C14 D3 G3 P4 Q4 R4 R5 S5 R9 Q12 R14 SETUP B C9 D5 C4 S4 S3 R3 Q3 O3 R6 R16 P17 P15 J17 COM Problem 162. White to play. White's stones don't seem to have any weaknesses. Therefore, this would be a good time to attack Black's moyo. How should White play ? ENDCOM W 1 K16 MARK A@J15 USER CORRECT ANSWER ENDUSER COM Correct Answer. If Black jumps to A, his moyo at the top will become huge. For that reason, the shoulder hit of White 1 is the right move. <= ENDCOM VAR W 1 K15 COM Failure. White 1 is not deep enough. ENDCOM B 2 L16 COM Black responds with 2, making a beautiful shape at the top and securing a lot of territory as well. <= ENDCOM ENDVAR VAR W 1 L17 COM Failure. A deep invasion at 1 is an overplay. ENDCOM B 2 K16 COM Even if White managed to live on the side, the thickness Black would get in the center is more than enough compensation. <= ENDCOM ENDVAR B 2 J16 W 3 K15 B 4 L18 W 5 J15 B 6 G16 COM The moves to Black 6 are the standard responses, but ... ENDCOM W 7 L17 B 8 M17 W 9 M16 B 10 K17 W 11 L16 MARK 7@L17 9@M16 COM ...with 7, 9, and 11, ... ENDCOM B 12 N17 W 13 N13 MARK 6@G16 COM ... then jumping to 13, White gets a large moyo in the center of the board. In spite of Black 6, White doesn't have to worry about her two stones in the upper left corner because the are quite tight. <= ENDCOM EVENT BOARDSIZE 19 SETUP W C17 D16 F16 L17 O17 Q18 K4 D4 F4 SETUP B R17 Q16 Q14 R9 Q3 M4 C6 B16 C14 C11 MARK 1@M4 COM Problem 163. White to play. Black has played 1, expanding the moyo he has made from the Chinese Opening and defying White to invade. How should White attack ? ENDCOM W 1 P9 USER CORRECT ANSWER ENDUSER COM Correct Answer. Lightly capping with White 1 is the correct strategy. It flattens Black's moyo ... ENDCOM VAR W 1 Q5 COM Failure. White 1 leaves something to be desired. ENDCOM B 2 R4 COM After Black 2, White must worry about being attacked. ENDCOM W 3 P9 COM If White now caps at 3, ... ENDCOM VAR W 3 Q7 COM If White jumps to 3 here, ... ENDCOM B 4 P9 COM ... Black jumps to 4, making a moyo at the top and leaving the two white stones below under attack. <= ENDCOM ENDVAR B 4 P8 COM ... Black attaches at 4. ENDCOM W 5 O8 B 6 Q8 W 7 O9 B 8 O7 W 9 N7 B 10 N6 MARK 1@Q5 COM After the sequence to Black 10, White 1 has become a wasted move. <= ENDCOM ENDVAR VAR W 1 B4 COM Failure. Locally, White 1 is an excellent move, but one of the strategic principles of Go is 'never let your opponent perfect his moyo.' ENDCOM B 2 P9 COM This is exactly what Black does when he jumps to 2. Black's moyo is now very large and solid and Black has taken a commanding lead. <= ENDCOM ENDVAR B 2 Q7 COM ... since he must answer at 2. There is still aji left in the corner. <= ENDCOM EVENT BOARDSIZE 19 SETUP W B17 C17 F18 F17 E16 D16 C15 F15 C3 C4 E2 L4 O3 R17 R16 R15 R13 SETUP B C18 D17 E17 E18 G18 G17 G16 F16 C16 F13 D4 D5 G4 Q4 R6 P17 Q15 Q14 COM Problem 164. White to play. Black is fairly thick at the top, but he still needs one more move to strengthen his moyo there. Where should White invade ? ENDCOM W 1 N17 MARK A@P18 \t@R17 USER CORRECT ANSWER ENDUSER COM Correct Answer. Note the marked white stone in the corner: White has invested an extra stone in this area. There are three black stones to White's four. By playing 1, White is threatening to link up with her marked stone by attaching at A. ENDCOM VAR W 1 Q13 COM Failure. Pushing up with White 1 ... ENDCOM B 2 O14 COM ... just helps Black get in the move he needs to strengthen his position. <= ENDCOM ENDVAR B 2 O16 COM Black 2, which prevents the link-up, is the strongest response. ENDCOM VAR B 2 N15 COM Variation. If Black caps with 1, ... ENDCOM W 3 P18 MARK B@Q18 A@O18 COM ... White attaches with 2. Black has two choices: A and B. ENDCOM B 4 O18 COM Bad for Black. Let's look at Black 1 first. This is not a severe move. ENDCOM VAR B 4 Q18 COM Variation. Black strongly resists with 4, but ... ENDCOM W 5 P16 COM ... White attacks by attaching on top with 2. ENDCOM VAR W 5 Q17 MARK 4@Q18 COM Failure. White 5 in response to Black 4 is bad. ENDCOM B 6 O18 W 7 P16 B 8 O17 W 9 O16 B 10 N16 MARK A@Q16 COM After the moves to Black 10, the cutting point at A is left behind. <= ENDCOM ENDVAR B 6 O17 W 7 O16 B 8 N16 MARK 6@O17 COM Black continues to resist with 6 and 8, but ... ENDCOM W 9 O18 B 10 Q17 W 11 Q16 MARK 9@O18 COM ... White plays 9 and 11 and, ... ENDCOM B 12 N18 W 13 M17 B 14 P19 W 15 M18 B 16 O19 W 17 R18 COM ... with the moves to 17, White will capture the black stones. <= ENDCOM ENDVAR W 5 O17 B 6 Q18 W 7 P16 MARK 5@O17 COM White can easily link up with 5 and 7. <= ENDCOM ENDVAR W 3 N16 B 4 N15 COM However, because his own group still has weaknesses, he must continue with 4 ... ENDCOM W 5 M15 B 6 N14 COM ... and 6. ENDCOM W 7 L16 MARK B@L13 A@K18 5@M15 COM This enables White to settle her group with 5 and 7. White now need fear no attack because she can get a base with A or escape into the center with a knight move at B. <= ENDCOM EVENT BOARDSIZE 19 SETUP W C17 D16 F16 L17 O17 Q18 K4 D4 F4 P9 SETUP B R17 Q16 Q14 R9 Q7 Q3 M4 C6 C11 C14 B16 MARK B@Q11 1@P9 2@Q7 A@R10 COM Problem 165. White to play. After the exchange of White 1 for Black 2, White's first instinct may be to attach at A. There is an interesting move here. Where should White play ? ENDCOM W 1 R3 MARK \t@Q7 USER CORRECT ANSWER ENDUSER COM Correct Answer. It seems as if Black has strongly reinforced the lower right by playing the marked stone. however, White can still attach at 1. The timing of this move is important; it must be played after Black has played the marked stone. ENDCOM B 2 R4 COM In response to Black 2, ... ENDCOM W 3 Q4 COM ... White cuts at 3. ENDCOM B 4 R5 MARK A@Q2 B@P3 C@S3 COM Black might extend to 4, but then White can live in the corner by playing A - Black B - White C. The way White plays is a strategic decision that depends on how the situation on the outside develops. ENDCOM VAR B 4 Q2 COM Variation. Black 4 is a fighting move. ENDCOM W 5 Q6 COM White attaches at 5, ... ENDCOM B 6 Q5 W 7 R6 B 8 P6 W 9 R7 B 10 Q8 W 11 R5 B 12 P4 W 13 S4 MARK 1@Q2 \t@R3 COM ... and the moves to 13 are one variation. The result is not so good for Black. Still, Black 1 is a solid move. Therefore, White's timing in playing the marked stone is important. <= ENDCOM ENDVAR W 5 P11 COM In the meantime, White simply jumps to 2, threatening the right side. It is decisions such as these that make Go so interesting. <= ENDCOM EVENT BOARDSIZE 19 SETUP W C18 D18 C17 C15 C14 B15 A14 B13 F17 F16 F15 Q17 Q15 R10 Q4 K4 SETUP B B12 C13 D14 D15 D16 D17 E17 E18 G16 G18 J16 M16 M13 E3 C4 D10 COM Problem 166. White to play. How should White play ? Aim at the cutting points on the left side ? Pull out the three stones within Black's moyo ? Is there some other overall strategy ? ENDCOM W 1 M11 MARK A@M10 USER CORRECT ANSWER ENDUSER COM Correct Answer. If White did nothing, a two-space jump at Black A would be a marvellous move. Therefore, White must stop Black somewhere along this line, and the cap of White 1 is the vital point in this battle of moyos. ENDCOM VAR W 1 F13 COM Failure. A move like 1, where White tries to pull his stones out of the pit of Black's moyo, ... ENDCOM B 2 G11 COM ... is a losing strategy. <= ENDCOM ENDVAR VAR W 1 Q3 COM Failure. Locally, White 1 is a big move, but ... ENDCOM B 2 M10 COM ... in this game Black 2 is so big that White must first deal with is before anything else. <= ENDCOM ENDVAR B 2 K12 COM If Black 2, ... ENDCOM W 3 K10 COM ... White continues with 3 and White is following a winning grand strategy. <= ENDCOM EVENT BOARDSIZE 19 SETUP W D17 C15 D4 P4 K3 M3 N3 O3 O18 P18 Q17 R17 S17 S16 SETUP B R4 P3 Q3 O4 O5 M4 Q10 K16 N17 O17 P17 Q16 R16 S15 R14 MARK 12@R14 11@S17 10@S15 9@S16 8@N17 6@O17 7@O18 5@P18 4@P17 3@Q17 MARK 2@R16 1@R17 COM Problem 167. White to play. White has taken the territory in the upper right corner, completing her profit-oriented strategy. But she must now cut Black's moyo down to size. To find the right move, you need to rely intuition rather than analysis. ENDCOM W 1 M9 MARK \t@P4 \t@N7 \t@M10 \t@L13 \t@O5 \t@K16 USER CORRECT ANSWER ENDUSER COM Correct Answer. Before discussing the solution, we will show you how to determine the limits of your invasion. We have marked the line stretching from the outermost black stones (marked) enveloping his moyo. If your move is outside this line, you should have no problems, but it might be not enough to win. If it's inside this line, your stone could end up being captured. You have to find the 'golden mean'. It is best to approach outside the line, your answer should be to play 1 towards the bottom. Why ? Compare the top and bottom parts of this moyo. On the lower right, White has a marked stone in place. Another stone played in this area could bring the aji of this stone to life. Therefore, it will be easier to make sabaki in this area. ENDCOM VAR W 1 L9 MARK \t@N7 \t@M10 \t@L13 COM Failure. The erasure of White 1 is too shallow. ENDCOM B 2 N9 MARK 1@L9 COM Black 2 hits just the right balance in expanding his moyo. Any wider and Black would be overextended. White 1 cannot be considered a good erasure <= ENDCOM ENDVAR VAR W 1 N9 MARK \t@N7 \t@M10 \t@L13 COM Failure. In contrast, White 1 is too deep. ENDCOM B 2 L9 COM Black would immediately cap at 2. ENDCOM W 3 P9 B 4 Q9 W 5 P7 B 6 Q8 W 7 M7 COM White's stones are not in danger of being captured, but ... ENDCOM B 8 L4 COM ... after Black 8, White has also to worry about her stones at the bottom. <= ENDCOM ENDVAR VAR W 1 M10 MARK \t@N7 \t@L13 COM Failure. White plays 1 one line higher than the Correct Answer. This approaches Black's thick wall at the top, so it doesn't have a good feel to it. ENDCOM B 2 K10 COM After Black 2, it is going to be hard for White to make sabaki. <= ENDCOM ENDVAR VAR W 1 M11 MARK \t@N7 \t@M10 \t@L13 COM Failure. Suppose White plays even one more line higher. This is clearly a bad move. ENDCOM B 2 K10 COM After Black 2, it is going to be even harder for White to make sabaki. As the proverb says, 'Don't approach thickness !' <= ENDCOM ENDVAR VAR W 1 D9 COM Failure. White 1 is too slow. It breaks the iron rule of not allowing your opponent to perfect his moyo. ENDCOM B 2 J10 MARK \t@N7 \t@M10 \t@L13 A@K10 COM Black will play 2 (or just A) and what was before only a moyo has almost become territory. In contrast, White 1 is not a very big move. <= ENDCOM ENDVAR B 2 K9 COM If Black caps with 2, ... ENDCOM VAR B 2 O9 COM If Black defends with 2, ... ENDCOM W 3 M11 COM ... White jumps to 3. White's stones are working throughout the board and the limits of the black moyo have been defined. <= ENDCOM ENDVAR W 3 P9 COM ... White plays 3 ... ENDCOM B 4 Q9 W 5 P8 COM ... and 5, seeking sabaki. However, all your moves should be natural. Do not make unreasonable moves, trying to trick Black. <= ENDCOM EVENT BOARDSIZE 19 SETUP W E17 E18 D17 D16 F16 D15 C9 R3 Q3 O3 O2 Q18 O17 M16 L16 L15 D3 SETUP B C18 D18 C17 C16 F17 C14 M3 N5 Q4 P4 R4 Q10 Q16 Q14 K14 L14 M15 N15 MARK 7@K14 6@L16 5@L14 4@L15 3@M15 2@M16 1@N15 COM Problem 168. White to play. This position is taken from a game played between Takemiya (Black) and Otake. Takemiya likes to map out big moyos and that is what he has done here. Where do you think Otake should play ? ENDCOM W 1 L9 MARK \t@L11 \t@M8 \t@N5 \t@K14 C@Q6 B@N4 A@L5 USER CORRECT ANSWER ENDUSER COM Correct Answer. We have marked another line for your convenience. If you were Otake, would you have entered into the black moyo as far as White 1 ? Black has a lot of weak point at A, B, and C, so you want to play within striking distance of these points. This is why Otake decided to play at 1. ENDCOM VAR W 1 M9 MARK \t@M8 \t@L11 COM Failure. A deep invasion with White 1 cannot be dismissed, but ... ENDCOM B 2 K9 COM ... the cap of Black 2 could be troublesome. White's stone would probably live, but with Black's thickness above it, it would be hard for White to gain any advantage. <= ENDCOM ENDVAR VAR W 1 K9 MARK \t@M8 \t@L11 COM Failure. White 1 is not a good erasing move. ENDCOM B 2 M9 MARK B@R10 A@R12 COM Black would answer with 2. There may still be an invasion at A, but Black would defend at B and get a lot of territory below. <= ENDCOM ENDVAR VAR W 1 L10 MARK \t@M8 \t@L11 COM Failure. White 1 is too near the thick black wall above, so it cannot be very good. ENDCOM B 2 D5 COM For the time being, Black would play at 2, just as in the actual game. <= ENDCOM ENDVAR VAR W 1 D5 COM Failure. White 1 ... ENDCOM B 2 K9 MARK \t@M8 \t@L11 COM ... lets Black perfect his moyo with 2. White will make some intrusion into it, but Black can expect a large territory around here when the game is over. = ENDCOM ENDVAR B 2 N9 COM Takemiya was concerned about an invasion. If he played 2, ... ENDCOM VAR B 2 J9 COM If Black played a capping move with 2, however, ... ENDCOM W 3 L7 COM ... White would jump to 3. Black has no follow-up, so the game would be easy for White. <= ENDCOM ENDVAR VAR B 2 D5 COM How the game continued. Black switched from the center to the lower left with 2 and ... ENDCOM W 3 F4 B 4 D8 W 5 C8 B 6 D7 W 7 E10 B 8 C3 W 9 C2 B 10 C4 W 11 E2 B 12 C7 COM ... played the moves to 12. ENDCOM W 13 C12 COM After exchanging 13 ... ENDCOM B 14 C13 COM ... for 14, ... ENDCOM W 15 O10 COM ... White came back to the right and played 15. It is hard to say which side has the advantage. <= ENDCOM ENDVAR W 3 R12 COM ... the invasion at 3 would be very disconcerting. <= ENDCOM EVENT BOARDSIZE 19 SETUP W C17 D16 F17 C12 C8 C6 D4 E3 R17 Q17 O17 O18 L4 M4 N4 O3 SETUP B B16 C14 E14 D11 C10 E8 M17 N15 P16 Q16 R16 Q10 Q4 Q6 N5 M5 K6 MARK 5@K6 4@M4 3@M5 2@N4 1@N5 COM Problem 169. White to play. Black maps out a huge moyo with the moves to 5. The way you counter it must be considered carefully. Do you go in lightly or with a bang ? ENDCOM W 1 R8 USER CORRECT ANSWER ENDUSER COM Correct Answer. Jumping in with White 1 was chosen because there was every expectation that White could live on the right side by playing this move. ENDCOM VAR W 1 R5 USER CORRECT ANSWER ENDUSER COM Correct Answer. It is also possible to play 1 here, and it would not be easy to kill this stone. <= ENDCOM ENDVAR VAR W 1 L10 COM Failure. If White wanted to make an erasing move, White 1 would be a good guess. ENDCOM B 2 N10 COM Black would respond by playing 2 and White's stone seems to be a little out of focus. It is always a perplexing problem to decide whether to erase or invade. You have to consider the distribution of stones, which stones are weak, the scale of the moyo, etc., in making your decision. <= ENDCOM ENDVAR B 2 Q8 COM If Black attaches with 2, ... ENDCOM VAR B 2 R10 MARK 1@R8 COM Variation. If Black defends with 2, White will look on 1 as a probe ... ENDCOM W 3 M9 COM ... and play 3. <= ENDCOM ENDVAR VAR B 2 R9 COM The actual game. In the actual game, Black attacked with 2. ENDCOM W 3 P9 COM White 3, escaping lightly, is a skilful move. ENDCOM B 4 O5 W 5 Q7 MARK 1@R8 COM The stones at 1 and 5 will probably sacrificed. ENDCOM B 6 R6 W 7 P10 B 8 P11 W 9 O11 B 10 Q9 W 11 O12 B 12 Q12 W 13 P14 B 14 R14 W 15 L12 MARK 5@Q7 1@R8 COM They should be considered as decoys while White goes about the main business of erasing Black's moyo with the moves up to 15. <= ENDCOM ENDVAR W 3 R9 B 4 Q9 W 5 S6 B 6 R10 W 7 R5 B 8 Q5 W 9 R3 COM ... up to White 9, Black gets a strong wall on the outside. But White is not dissatisfied with the territory she has gotten on the right. What is worrisome is the blackness that pervades the center of the board. White has two ways into the center. ENDCOM B 10 G16 COM Black blocks one of then by pressing with 10 ... ENDCOM W 11 G17 B 12 H16 COM ... and 12. ENDCOM W 13 J7 COM However, White can still come in with 13, so she is satisfied. <= ENDCOM EVENT BOARDSIZE 19 SETUP W D16 D10 D4 F4 G4 H3 J3 Q18 O17 L17 SETUP B G3 H4 H5 K4 K3 Q3 Q5 Q9 Q16 Q14 R17 COM Problem 170. Black to play. Where should Black play so as to decrease the size of White's moyo while increasing the size of his own ? ENDCOM B 1 M15 USER CORRECT ANSWER ENDUSER COM Correct Answer. Black should expand his moyo with 1. ENDCOM W 2 K16 COM If White defends with 2, ... ENDCOM B 3 K14 COM ... Black continues to expand with 3. The scale of Black's moyo is now larger than White's. <= ENDCOM EVENT BOARDSIZE 19 SETUP W D16 D10 D4 F4 G4 H3 J3 Q18 O17 L17 SETUP B G3 H4 H5 K4 K3 Q3 Q5 Q9 Q14 Q16 R17 K15 MARK 1@K15 COM Problem 171. White to play. Black has played 1. This is not such a good move. How should White counter it ? ENDCOM W 1 M16 USER CORRECT ANSWER ENDUSER COM Correct Answer. Although it may seen strange, White 1 is the correct response. You might want to make a more aggressive move to erase the black moyo, but White must be patient. You have to make your base strong before launching an all-out attack. ENDCOM VAR W 1 J16 COM Failure. White 1 is a losing move. ENDCOM B 2 M16 W 3 M17 B 4 O16 MARK 2@M16 COM Black plays 2 and 4 in sente, mapping out a huge moyo in the center. ENDCOM W 5 P17 MARK A@C17 COM Next, Black can aim at invading the 3-3 point with A, so White's territory at the top is not so big. It is clear that White is the big loser in this exchange. <= ENDCOM ENDVAR VAR W 1 L15 USER CORRECT ANSWER ENDUSER COM Correct Answer. For reference, let's look at another way White could answer Black's erasure move. Against White 1, ... ENDCOM B 2 L16 W 3 M16 B 4 K16 MARK 2@L16 COM ... Black responds with 2 and 4. ENDCOM W 5 K17 B 6 K13 W 7 M15 B 8 H16 COM After Black jumps to 8, ... ENDCOM W 9 M13 COM ... White can also jump to 9. Black's position is not good. However, the moves in the Correct Answer are much clearer. <= ENDCOM ENDVAR B 2 M14 COM In order to prevent an intrusion into his moyo, Black drops back to 2. ENDCOM VAR B 2 K17 COM Variation. If Black attaches at 2, ... ENDCOM W 3 K18 B 4 J17 W 5 J18 MARK 3@K18 COM ... White plays 3 and 5. ENDCOM B 6 G17 COM After Black 6, ... ENDCOM W 7 M14 COM ... White punches a big hole in Black's moyo with 7. It's hard to say which side has the more favourable position, but at least White has as much chance as Black of winning. <= ENDCOM ENDVAR W 3 L14 COM However, because the ladder is favourable for White, 3 is a sever tesuji. ENDCOM B 4 L15 W 5 M15 B 6 M13 COM Black must extend to 6, but ... ENDCOM W 7 L13 B 8 L12 W 9 J14 MARK 7@L13 COM ... then 7 and 9 are powerful moves, challenging Black to a fight he cannot win. <= ENDCOM