EVENT
BOARDSIZE 19
SETUP W D18 D17 C15 O16 Q17 R17 R14 Q13 Q10 Q9 Q8 N9 R7 S7 S6 R6 S5 S4 R3 R2 
SETUP B E17 E16 K16 Q16 R15 Q14 R13 R12 R11 R10 R8 S8 T7 Q3 Q4 R5 Q6 Q7 K4 D4 
MARK \t@N9 \t@Q10 \t@Q9 \t@Q8
COM
Problem 24. Black to play.  

White's marked stones are vulnerable, but Black's stones at the
top are also thin. What should Black do ? 
ENDCOM
B 1 L9
MARK \t@Q8 \t@Q10 \t@Q9 \t@N9
USER
CORRECT ANSWER
ENDUSER
COM
Correct Answer.

Black should first go after the marked white stones on the right
by capping with 1, ...
ENDCOM
W 2 N11
B 3 L11
COM
... drive them towards the top with 3 ...
ENDCOM
W 4 N13
B 5 L13
COM
... and 5.
ENDCOM
W 6 N15
B 7 D14
MARK 6@N15
COM
After White 6, Black puts pressure on the white stones on the
left with 7 ...
ENDCOM
W 8 C14
B 9 D13
COM
... and 9.
ENDCOM
W 10 C13
B 11 D11
W 12 D12
B 13 E12
W 14 C12
B 15 E11
COM
With 15, Black ends in gote, but his stones on the top are no
longer thin and he has built a moyo in the center. Black has
an overwhelming advantage.
<=
ENDCOM