EVENT
BOARDSIZE 19
SETUP W D13 D12 D15 D16 D17 E17 E18 H17 K3 D3 D4 D5 E7 C8 
SETUP B C18 D18 C17 C16 C14 C13 F17 Q16 Q3 R5 B6 C6 C4 C3 
MARK C@M3 A@N16 B@Q10
COM
Problem 126. Black to play.  

White is thick at the left side from the top to the bottom. Although
Black has a lot of profit, he still has to prevent White from
expanding the scale of her moyo. Where should he play ? 
ENDCOM
B 1 N16
USER
CORRECT ANSWER
ENDUSER
COM
Correct Answer.

Black 1 blocks White from making a large-scale moyo at the top
while making territory.
ENDCOM
  VAR
  B 1 M3
  COM
  Failure.

  Locally, Black 1 here is big, but ...
  ENDCOM
  W 2 N16
  COM
  ... it is too dangerous to let White play at 2.
  <=
  ENDCOM
  ENDVAR
  VAR
  B 1 Q10
  COM
  Failure.

  Black 1 is not good ...
  ENDCOM
  W 2 O16
  COM
  ... because it lets White make an approach move at 2.
  ENDCOM
  B 3 Q14
  W 4 Q17
  B 5 R17
  W 6 P17
  B 7 R18
  W 8 O14
  COM
  After the sequence to 8, White has made a huge moyo at the top.
  <=
  ENDCOM
  ENDVAR
W 2 O3
COM
If White answers with 2, ...
ENDCOM
B 3 L5
W 4 O5
B 5 J5
W 6 K6
B 7 K5
W 8 M3
B 9 H7
COM
... Black is satisfied to erase White's moyo with the sequence
to 9.
<=
ENDCOM