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BOARDSIZE 19
SETUP W J17 N16 O17 N18 P16 L16 
SETUP B D16 G17 P17 Q17 R16 R14 M17 K18 
MARK \t@L16
COM
Problem 39. Black to play.  

In response to the marked white stone, Black has a tesuji that
he must play. Where is it ? 
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B 1 K16
USER
CORRECT ANSWER
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COM
Correct Answer.

Attaching with 1 is Black's tesuji.
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  VAR
  B 1 J18
  COM
  Failure.

  Simply crawling with 1 ...
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  W 2 L17
  COM
  ... lets White play 2, giving her thickness on the outside.
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  ENDVAR