EVENT
BOARDSIZE 19
SETUP W K15 Q17 R15 
SETUP B D16 D14 C10 H16 K17 
MARK 1@K15 2@H16
COM
Problem 104. White to play.  

White flattens Black's moyo at the top left by exchanging 1 for
Black 2. How should White continue ? 
ENDCOM
W 1 C17
USER
CORRECT ANSWER
ENDUSER
COM
Correct Answer.

It is urgent for White to invade at the 3-3 point. If White neglects
to play here - (see Variation to this move)
<=
ENDCOM
  VAR
  W 1 K10
  COM
  (White 1 is played here to get 'Black to move').
  ENDCOM
  B 2 D17
  COM
  Black will add another stone at 2. All the territory in the top
  left part of the board will become Black's.
  <=
  ENDCOM
  ENDVAR