EVENT
BOARDSIZE 19
SETUP W C13 C14 C15 D15 E16 F16 G16 D4 Q6 P13 Q11 
SETUP B C17 C16 D16 E17 F17 B15 B14 O4 Q3 Q16 O16 R13 
MARK A@D6 C@G3 B@O6 D@K3
COM
Problem 151. White to play.  

White is satisfied with her thickness in the upper left. However,
she would like to use this thickness to build a moyo. Where should
she play ? 
ENDCOM
W 1 O6
USER
CORRECT ANSWER
ENDUSER
COM
Correct Answer.

Since the right side is thin, White should first strengthen it
by jumping to 1.
ENDCOM
  VAR
  W 1 D6
  COM
  Failure.

  If White prematurely plays on the left with 1, ...
  ENDCOM
  B 2 O6
  MARK A@Q9
  COM
  ... Black will jump to 2, aiming at an invasion at A.
  ENDCOM
  W 3 R4
  B 4 R3
  W 5 Q8
  B 6 J4
  COM
  After extending to 6. Black's positions on both the right and
  left sides have been settled.
  <=
  ENDCOM
  ENDVAR
B 2 M4
MARK A@M3
COM
Black 2 at A is bad because it is too low.
ENDCOM
W 3 D7
COM
Next, White 3 starts to build a moyo on the left side.
<=
ENDCOM