EVENT
BOARDSIZE 19
SETUP W F17 F16 K17 R16 R15 Q14 P14 
SETUP B D16 E17 D14 N17 Q16 Q15 R17 S17 R14 R10 
MARK 3@R14 2@Q14 1@Q15 \t@P14
COM
Problem 127. White to play.  

After White plays the marked stone, Black pushes down and cuts
with 1 and 3. What should White do ? 
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W 1 R13
USER
CORRECT ANSWER
ENDUSER
COM
Correct Answer.

White should atari with 1, ...
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B 2 S14
W 3 P16
COM
... then attach at 3.
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B 4 Q17
  VAR
  B 4 S15
  MARK 3@P16
  COM
  Failure.

  If Black ignores White 3 and immediately goes after the two white
  stones with 4, ...
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  W 5 P15
  B 6 Q17
  W 7 P17
  MARK 5@P16
  COM
  ... White plays 5 and 7, isolating the black stone at the top.
  <=
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  ENDVAR
W 5 S13
B 6 S15
COM
After Black 6, ...
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W 7 P12
COM
... White makes shape with 7.
<=
ENDCOM