EVENT
BOARDSIZE 19
SETUP W C16 C15 D17 D18 E18 E16 F17 F15 G16 C3 C6 D4 Q5 R10 R13 
SETUP B B17 C17 D16 D15 E15 E14 C14 D13 D2 F3 J3 O4 Q3 R16 P16 
COM
Problem 89. White to play.  

The proverb advises us, "Don't play near thickness !" White has
thickness in the top left and Black on the upper side, but White
is thin on the right. Where should White play ? 
ENDCOM
W 1 N17
MARK B@M17 A@Q17
USER
CORRECT ANSWER
ENDUSER
COM
Correct Answer.

White should extend all the way to 1. This move is the proper
distance from her thickness on the left and also aims at A, the
weak point of Black's corner enclosure. White 1 at B would be
too close to her thickness.
<=
ENDCOM
  VAR
  W 1 R3
  COM
  Failure.

  Locally, playing the sequence from White 1 ...
  ENDCOM
  B 2 R2
  W 3 R4
  B 4 S2
  W 5 Q7
  COM
  ... to 5 is good, but ...
  ENDCOM
  B 6 M17
  COM
  ... Black will then play 6, erasing the influence of White's
  thickness and defending the weak underbelly of his corner enclosure
  at the top.
  <=
  ENDCOM
  ENDVAR