EVENT
BOARDSIZE 19
SETUP W D16 D4 K4 R14 
SETUP B Q3 Q9 Q16 K16 
MARK 1@R14
COM
Problem 75. Black to play.  

Black welcomes White's approach at 1. Now he can utilise the
power of his Chinese-opening formation to attack White. Where
is the strongest move ? 
ENDCOM
B 1 R15
USER
CORRECT ANSWER
ENDUSER
COM
Correct Answer.

Black should attach at 1, ...
ENDCOM
  VAR
  B 1 O16
  COM
  Failure.

  Black 1 is a bad move.
  ENDCOM
  W 2 S16
  COM
  White can settle her stones by sliding to 2 ...
  ENDCOM
  B 3 R17
  W 4 R11
  MARK \t@Q9
  COM
  ... and extending to 4. As a result, the marked stone is misplaced
  and Black's Chinese-opening strategy has fallen apart.
  <=
  ENDCOM
  ENDVAR
  VAR
  B 1 R12
  COM
  Failure.

  The pincer of Black 1 is not good.
  ENDCOM
  W 2 R17
  COM
  White will invade with 2.
  ENDCOM
  B 3 R16
  W 4 Q17
  B 5 P16
  W 6 S16
  B 7 S15
  W 8 S17
  B 9 R15
  W 10 O17
  MARK A@Q5 \t@Q9
  COM
  After White 10, the marked stone is too near the thickness above.
  This stone would be more efficient if it were at A.
  <=
  ENDCOM
  ENDVAR
W 2 Q14
COM
... forcing White to stand at 2.
ENDCOM
B 3 O16
W 4 Q11
MARK \t@Q9
COM
Because of the marked stone, White can extend only as far as
4. Next, Black will attack the three white stones.
<=
ENDCOM