EVENT
BOARDSIZE 19
SETUP W D16 D14 R3 O2 O3 N4 O5 O6 P6 P7 P8 R8 O9 M6 M5 L6 L5 K5 K4 L4 J4 H5 G5 D4 
SETUP B F17 L17 R16 R11 Q4 S5 Q6 P3 P2 O7 N7 M7 L7 K6 J6 N6 N5 G3 H3 K3 L3 M3 M4 
MARK \t@G5 \t@H5 \t@J4 \t@K4 \t@K5 \t@L5 \t@L4 \t@M5 \t@M6 \t@L6
COM
Problem 33. Black to play.  

How should Black attack the marked white stones ? 
ENDCOM
B 1 G7
USER
CORRECT ANSWER
ENDUSER
COM
Correct Answer.

Black attacks with 1, ...
ENDCOM
W 2 E5
COM
... and White must defend with 2.
ENDCOM
B 3 D2
COM
Black 3 is now the key move.
ENDCOM
  VAR
  B 3 E8
  MARK 2@E5
  COM
  Failure.

  After White 2, Black 3 looks like a strong move, but ...
  ENDCOM
  W 4 E3
  COM
  ... White will attack the black stones at the bottom with 4 ...
  ENDCOM
  B 5 F2
  W 6 E2
  MARK B@K8 A@J2
  COM
  ... and 6. White A now threatens to kill them, so Black must
  defend in gote. White's stones on the left are secure, so she
  can attack with a peep at B.
  <=
  ENDCOM
  ENDVAR
W 4 D8
MARK A@E8
COM
White must defend by playing around 4. I f White neglects to
play here, Black A will be severe.
ENDCOM
B 5 M10
COM
Black now switches his attack to the right with 5 ...
ENDCOM
W 6 O11
B 7 M12
COM
... and 7.  The white stones on the right are in danger and Black
is building a moyo in the center.
<=
ENDCOM