EVENT
BOARDSIZE 19
SETUP W D16 C14 D3 G3 P4 Q4 R4 R5 S5 R9 Q12 R14 
SETUP B C9 D5 C4 S4 S3 R3 Q3 O3 R6 R16 P17 P15 J17 
COM
Problem 162. White to play.  

White's stones don't seem to have any weaknesses. Therefore,
this would be a good time to attack Black's moyo. How should
White play ? 
ENDCOM
W 1 K16
MARK A@J15
USER
CORRECT ANSWER
ENDUSER
COM
Correct Answer.

If Black jumps to A, his moyo at the top will become huge. For
that reason, the shoulder hit of White 1 is the right move.
<=
ENDCOM
  VAR
  W 1 K15
  COM
  Failure.

  White 1 is not deep enough.
  ENDCOM
  B 2 L16
  COM
  Black responds with 2, making a beautiful shape at the top and
  securing a lot of territory as well.
  <=
  ENDCOM
  ENDVAR
  VAR
  W 1 L17
  COM
  Failure.

  A deep invasion at 1 is an overplay.
  ENDCOM
  B 2 K16
  COM
  Even if White managed to live on the side, the thickness Black
  would get in the center is more than enough compensation.
  <=
  ENDCOM
  ENDVAR
B 2 J16
W 3 K15
B 4 L18
W 5 J15
B 6 G16
COM
The moves to Black 6 are the standard responses, but ...
ENDCOM
W 7 L17
B 8 M17
W 9 M16
B 10 K17
W 11 L16
MARK 7@L17 9@M16
COM
...with 7, 9, and 11, ...
ENDCOM
B 12 N17
W 13 N13
MARK 6@G16
COM
... then jumping to 13, White gets a large moyo in the center
of the board. In spite of Black 6, White doesn't have to worry
about her two stones in the upper left corner because the are
quite tight.
<=
ENDCOM