EVENT
BOARDSIZE 19
SETUP W D16 C14 L17 L16 L14 M13 R17 R16 R14 S14 L3 C3 D4 F3 
SETUP B F17 J16 K17 K14 L13 Q17 Q16 Q15 P13 R12 Q4 B4 C6 C9 
MARK \t@M13
COM
Problem 133. Black to play.  

White has just played the marked stone (see Problem 57). How
should Black counter this move ? 
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B 1 L15
USER
CORRECT ANSWER
ENDUSER
COM
Correct Answer.

Black should atari at 1.
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W 2 M15
COM
White has no choice but to block with 2.
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B 3 M14
W 4 N14
B 5 L14
COM
After Black connects with 5, ...
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W 6 O15
B 7 Q14
W 8 N16
COM
... the sequence to 8 is inevitable.
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B 9 M12
W 10 N13
B 11 N12
W 12 R18
B 13 O17
W 14 N17
B 15 O13
COM
Black now builds a wall in the center.
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W 16 O18
COM
White can live with her stones by playing 16, but Black ends
in sente. Black's thick wall in the center gives him a huge advantage.
<=
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