EVENT
BOARDSIZE 19
SETUP W J17 N16 O17 P16 N18 
SETUP B D16 G17 M17 K18 P17 Q17 R16 R14 
MARK 1@K18
COM
Problem 36. White to play.  

How does White respond to Black 1 ? 
ENDCOM
W 1 L16
USER
CORRECT ANSWER
ENDUSER
COM
Correct Answer.

White 1 is the only move.
<=
ENDCOM
  VAR
  W 1 J18
  COM
  Failure.

  Preventing Black from linking up with 1 fails.
  ENDCOM
  B 2 K17
  W 3 J16
  B 4 L15
  MARK 2@K17
  COM
  Black plays 2 and 4 and the white stones on both sides come under
  siege.
  <=
  ENDCOM
  ENDVAR
  VAR
  W 1 K17
  COM
  Failure.
  ENDCOM
  B 2 L17
  W 3 J18
  B 4 L15
  COM
  <=
  ENDCOM
  ENDVAR