EVENT
BOARDSIZE 19
SETUP W L17 P16 Q17 R17 
SETUP B D17 C15 J17 S17 R16 S15 Q14 
MARK \t@Q14 \t@J17
COM
Problem 37. Black to play.  

Since Black has played the two marked stones, he dominates the
top of the board. From this strength, where should he invade
? 
ENDCOM
B 1 N17
USER
CORRECT ANSWER
ENDUSER
COM
Correct Answer.

Jumping into the middle of White's formation with 1 is the vital
point.
ENDCOM
W 2 N16
COM
If White attaches with 2, ...
ENDCOM
B 3 M17
W 4 M16
B 5 L18
W 6 L16
  VAR
  W 6 O17
  COM
  Variation.

  If White settles herself with 6, ...
  ENDCOM
  B 7 L16
  W 8 L15
  B 9 K16
  MARK 7@L16
  COM
  ... Black is more than happy to play 7 and 9.
  <=
  ENDCOM
  ENDVAR
B 7 K17
COM
... Black links up his stones with the moves to 7.
<=
ENDCOM