EVENT
BOARDSIZE 19
SETUP W D16 Q4 C1 B2 B3 B4 C4 D3 E3 D2 F5 
SETUP B Q16 D4 E4 F4 G4 F3 C5 D6 E2 
COM
Problem 92. Black to play.  

In the lower left corner, White has taken profit while Black
has made thickness and ended in sente. Black must now make an
approach move against one of the white stones. Which approach
move should he make ? 
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B 1 O3
USER
CORRECT ANSWER
ENDUSER
COM
Correct Answer.

Approaching the lower right corner with Black 1 is the best move.
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  VAR
  B 1 C14
  COM
  Failure.

  If Black approaches the stone in the upper left with 1, ...
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  W 2 F17
  B 3 D11
  MARK A@B6
  COM
  ... Black cannot be certain of getting the territory on the left
  side after 3 because White has a big endgame move at A.
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  W 4 N3
  COM
  Next, White extends to 4, curtailing the influence of Black's
  thickness at the bottom.
  <=
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  ENDVAR
W 2 R6
MARK A@Q6
COM
Instead of 2, White A is also a good move.
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B 3 L4
MARK B@C14
COM
Black gets an ideal position at the bottom when he plays 3. An
approach move at B would be in the wrong direction.
<=
ENDCOM