EVENT
BOARDSIZE 19
SETUP W D16 D4 R14 P16 O17 P17 Q17 R17 O15 O14 O13 
SETUP B K4 Q4 Q10 Q13 R13 Q15 P15 Q16 R16 O16 N16 M15 
COM
Problem 152. White to play.  

Both White and Black have weak stones in the center. How should
White continue ? 
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W 1 M13
USER
CORRECT ANSWER
ENDUSER
COM
Correct Answer.

White should force once with 1, ...
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  VAR
  W 1 D10
  COM
  Failure.

  White must defend her stones on the right. If she makes a sanren-sei
  on the left with 1, ...
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  B 2 M13
  COM
  ... Black will go on the offensive with the sequence from 2 ...
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  W 3 O11
  B 4 M11
  W 5 O9
  B 6 M9
  W 7 O7
  B 8 Q7
  COM
  ... to 8. Black has secured territory on the right, made influence
  in the center, and White's stones are in big trouble.
  <=
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  ENDVAR
B 2 K15
  VAR
  B 2 N17
  COM
  Black could also play 2 here, but White's stones in the corner
  are safe, so she could just ignore it.
  <=
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  ENDVAR
W 3 N10
COM
... then jump to 3, reducing the potential of Black's moyo at
the bottom. White's stones are now in no danger.
<=
ENDCOM