EVENT
BOARDSIZE 19
SETUP W D16 D3 
SETUP B Q4 R16 P17 
MARK 1@R16 5@P17 3@Q4 4@D3 2@D16
COM
Problem 52. White to play.  

What should White do after Black makes a corner enclosure with
5 ? 
ENDCOM
W 1 R10
USER
CORRECT ANSWER
ENDUSER
COM
Correct Answer.

White should break up Black's formation on the right side by
playing at 1.
<=
ENDCOM
  VAR
  W 1 C5
  COM
  Failure.

  Making a corner enclosure in the lower left corner with 1 is
  passive.
  ENDCOM
  B 2 R10
  COM
  Black will take this opportunity to build a strong formation
  on the right side with 2, which is an ideal extension from both
  the corner enclosure at the top and the star point at the bottom.
  <=
  ENDCOM
  ENDVAR