EVENT
BOARDSIZE 19
SETUP W C17 C16 D15 D13 C12 S17 S16 R16 Q17 P17 P16 N16 F17 H17 K16 K15 J15 H15 G15 H13 J12 K11 
SETUP B C18 D17 E18 E16 E15 E14 D4 Q4 R18 R17 Q16 Q15 R15 L16 L15 K17 J17 J16 G14 F12 K14 M14 L13 J10 
MARK A@J10 B@K11
COM
Problem 135. Black to play.  

When Black caps with A, White comes out diagonally with B. How
should Black continue his attack ? 
ENDCOM
B 1 L9
USER
CORRECT ANSWER
ENDUSER
COM
Correct Answer.

Exchanging Black 1 ...
ENDCOM
W 2 M11
COM
... for White 2 is natural, ...
ENDCOM
B 3 O14
COM
... but Black 3 is a move that many players would miss. However,
it is important because, if White were to play on this point,
the black stones at the top would be separated.
ENDCOM
W 4 N10
COM
White moves out with 4, ...
ENDCOM
  VAR
  W 4 N9
  MARK \t@O14
  COM
  Variation.

  In response to the marked stone, White might jump out into the
  center with the knight's move of 4.
  ENDCOM
  B 5 O11
  COM
  Black attacks with 5 ...
  ENDCOM
  W 6 N11
  B 7 O10
  COM
  ... and 7, ...
  ENDCOM
  W 8 M9
  B 9 S15
  COM
  ... makes a sente move with 9, ...
  ENDCOM
  W 10 S18
  B 11 P8
  COM
  ... then stakes out territory on the right side with 11.
  ENDCOM
  W 12 L8
  B 13 F10
  COM
  Black jumps out with 13, and ...
  ENDCOM
  W 14 K9
  COM
  ... White secures her stones in the center with 14.
  ENDCOM
  B 15 C10
  COM
  Black now attacks the white group in the upper left with 15 ...
  ENDCOM
  W 16 B11
  B 17 B10
  COM
  ... and 17; ...
  ENDCOM
  W 18 D14
  COM
  ... White must defend in gote with 18.
  ENDCOM
  B 19 F3
  COM
  Finally, Black reinforces his corner with 19.

  In this attack, Black hasn't really gone all out for the kill.
  Instead, he has built up his territory on the right with moves
  that threaten White's stones. He gets the initiative on the
  left by attacking the white stones in the upper left. Black is
  now far ahead. This is a good example of the correct way to attack.
  <=
  ENDCOM
  ENDVAR
B 5 Q11
COM
... but Black attacks with 5. This move is also sente against
the white stones in the corner, ...
ENDCOM
W 6 S18
COM
... so White must defend with 6.
ENDCOM
  VAR
  W 6 N8
  MARK \t@Q11
  COM
  White dies.

  White wants to jump to 6 in answer to the marked stone, but if
  she does, ...
  ENDCOM
  B 7 S18
  COM
  ... Black will turn at 7.
  ENDCOM
  W 8 S15
  COM
  White fights back by cutting through with 8 ...
  ENDCOM
  B 9 S14
  W 10 R14
  COM
  ... and 10. but ...
  ENDCOM
  B 11 Q14
  W 12 R13
  B 13 S13
  W 14 Q13
  B 15 P13
  W 16 R12
  B 17 S12
  W 18 R11
  B 19 R10
  W 20 S11
  B 21 S10
  COM
  ... the white stones on the right are dead after the sequence
  to Black 21.
  <=
  ENDCOM
  ENDVAR
B 7 N8
COM
Next, Black continues the attack with 7 ...
ENDCOM
W 8 P10
B 9 R9
COM
... and 9. The white stones are now in serious trouble.
<=
ENDCOM