EVENT
BOARDSIZE 19
SETUP W D17 C15 D6 D4 Q4 Q5 P3 Q2 O4 
SETUP B F3 K4 Q3 R3 R4 R5 R6 R16 P17 
COM
Problem 65. Black to play.  

There are big points still to be played on the left side and
at the top, but Black has an even bigger point somewhere else.
Where should he play ? 
ENDCOM
B 1 N3
MARK A@H3
USER
CORRECT ANSWER
ENDUSER
COM
Correct Answer.

Black 1 is a huge move. It attacks the white group on the right
and defends against an invasion at A.
ENDCOM
  VAR
  B 1 J17
  MARK A@C10
  COM
  Failure.

  Black 1 is certainly a big point, as is Black A on the left side,
  but ...
  ENDCOM
  W 2 H3
  COM
  ... the invasion of White 2 ...
  ENDCOM
  B 3 H4
  W 4 J4
  COM
  ... and 4 is severe.
  ENDCOM
  B 5 J5
  W 6 J3
  B 7 G4
  W 8 K3
  COM
  With the sequence to 8, White has settled her stones at the bottom
  and disrupted Black's stones there.
  <=
  ENDCOM
  ENDVAR
W 2 N4
B 3 M3
W 4 P7
B 5 Q8
COM
After Black 5, White's group is still unstable and Black will
build a moyo on the right side while attacking White.
<=
ENDCOM