EVENT
BOARDSIZE 19
SETUP W D17 B3 C4 B5 D7 G3 H3 H4 J5 K5 L4 L3 K2 L6 R3 R4 Q5 R9 
SETUP B C15 C11 C3 D3 E4 G4 G5 H5 L5 M5 M4 M3 L2 M1 N2 P2 Q3 R2 P17 R16 
MARK \t@C11
COM
Problem 80. White to play.  

Black has just played the marked stone. This is a big point,
but Black's six stones at the bottom left are still insecure.
What should White do ? 
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W 1 F3
USER
CORRECT ANSWER
ENDUSER
COM
Correct Answer.

White 1 is an important point because it takes away Black's eye
shape. Next ...
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  VAR
  W 1 R12
  COM
  Failure.

  Locally, White 1 is a good move, but ...
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  B 2 F3
  MARK A@J3
  COM
  ... Black can secure his stones with 2. Black's prospects are
  now quite good. If the white stones later need two eyes, White
  will have to come back to play A, so this bad aji will be a burden.
  <=
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  ENDVAR
B 2 D5
COM
Black will first play a forcing move with 2 to avoid being cut
into two, ...
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W 3 C7
B 4 H7
COM
... then jump into the center with 4. Black's stones are vulnerable,
but there is not a good way to attack them yet.
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W 5 R12
MARK 1@F3
COM
Therefore, White should take her time and simply play a big point
on the right side with 5. White 1 in the Correct Answer not only
robs Black of his base, it also ensures that White's group has
two eyes. For example, ...
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B 6 J2
COM
... if Black attacks with the sequence Black 6, ...
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W 7 J3
COM
... White 7, ...
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B 8 K1
COM
... Black 8, ...
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W 9 K3
COM
... White plays at 9 and she is alive.
<=
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