EVENT
BOARDSIZE 19
SETUP W D16 K16 O17 Q5 D4 
SETUP B Q16 Q14 Q9 Q3 R4 K4 
MARK A@O4 1@R4
COM
Problem 39. White to play.  

Instead of A, Black plays the diagonal move of 1. As we mentioned
in Problem 11, this is not a good move because Black's stones
become heavy. How should White respond ? 
ENDCOM
W 1 N5
USER
CORRECT ANSWER
ENDUSER
COM
Correct Answer.

The two-space jump of White 1 is a light move. Whenever you play
near your opponent's strong stones, playing lightly is an iron
rule.
<=
ENDCOM
  VAR
  W 1 P4
  USER
  CORRECT ANSWER
  ENDUSER
  COM
  Correct Answer.

  The diagonal move of White 1 is also a strong move.
  ENDCOM
  B 2 P3
  COM
  Against Black 2, ...
  ENDCOM
  W 3 N4
  COM
  ... White plays lightly with 3 ...
  ENDCOM
  B 4 O3
  W 5 N7
  COM
  ... and 5.
  ENDCOM
  B 6 O4
  COM
  Note the tesuji of Black 6 ...
  ENDCOM
  W 7 O5
  B 8 M4
  COM
  ... and 8. In any case, White should not be unhappy, since she
  has forced Black to crawl along the third line.
  <=
  ENDCOM
  ENDVAR
  VAR
  W 1 R5
  COM
  Failure.

  White gets a heavy shape if she plays 1.
  ENDCOM
  B 2 O4
  COM
  After Black 2, her two stones will come under a severe attack.
  <=
  ENDCOM
  ENDVAR