EVENT
BOARDSIZE 19
SETUP W D16 D10 C4 E3 R10 
SETUP B P3 R4 Q16 R12 R8 
MARK \t@R10
COM
Problem 7. Black to play.  

The marked white stone on the right is isolated within Black's
stronghold. How should Black attack ? 
ENDCOM
B 1 P10
USER
CORRECT ANSWER
ENDUSER
COM
Correct Answer.

Capping with Black 1 is severe. What happens if White tries to
escape ?
ENDCOM
  VAR
  B 1 Q11
  COM
  Wrong answer.

  The diagonal move of Black 1 is bad.
  ENDCOM
  W 2 Q10
  B 3 P10
  W 4 Q8
  B 5 R7
  W 6 P9
  B 7 O10
  COM
  The sequence continues to Black 7, but ...
  ENDCOM
  W 8 N8
  COM
  ... White's stones have made it into the open when she plays
  the knight's move of 8. Black has made little progress with his
  moves.
  <=
  ENDCOM
  ENDVAR
W 2 Q11
COM
The diagonal move of 2 on the right is White's best chance, since
Black is weaker there.
ENDCOM
B 3 O12
COM
But Black continues to attack with the knight's move of 3.
ENDCOM
  VAR
  B 3 Q12
  MARK \t@P10
  COM
  Wrong answer.

  Capping with the marked stone is a good move, but to continue
  by pushing up with 3 ...
  ENDCOM
  W 4 P11
  B 5 P12
  COM
  ... and 5 is the wrong direction.
  ENDCOM
  W 6 O11
  MARK A@R17
  COM
  White escapes into the center with 6. Black's territory in the
  upper left is still not secure, since a 3-3 point invasion at
  A still remains.
  <=
  ENDCOM
  ENDVAR
W 4 Q12
B 5 R13
W 6 Q13
MARK 4@Q12
COM
White must now push with 4 and 6, ...
ENDCOM
B 7 R14
MARK 5@R13
COM
... inducing Black to play 5 and 7.
ENDCOM
W 8 O13
B 9 N13
W 10 O14
B 11 Q14
W 12 P14
B 13 N14
W 14 O16
B 15 M16
COM
After the sequence to 15, White's stones are still in trouble.
For Black's part, he has strengthened his stones in the upper
right and built influence in the center. In contrast, White has
gained nothing.
<=
ENDCOM