EVENT
BOARDSIZE 19
SETUP W C17 D16 C14 D4 D6 K4 N4 Q14 R14 R11 
SETUP B D18 F17 J17 R15 Q16 O16 Q3 Q5 R9 P9 
MARK \t@D6
COM
Problem 14. Black to play.  

White has just played the marked stone, leaving her three stones
in the upper right to fend for themselves. How should Black attack
them ? 
ENDCOM
B 1 P11
MARK A@S12
USER
CORRECT ANSWER
ENDUSER
COM
Correct Answer.

Black 1 is the best way to attack in this position. Black now
aims at A.
ENDCOM
  VAR
  B 1 O14
  COM
  Failure.

  Attacking with Black 1 and ...
  ENDCOM
  W 2 P11
  B 3 N11
  COM
  ... 3 is in the wrong direction. Black's aim is to build a moyo
  towards the left, but ...
  ENDCOM
  W 4 S9
  B 5 S8
  W 6 S10
  MARK A@K16
  COM
  ... White secures her stones with the sequence to 6, leaving
  the black stones in the lower right thin. Next, White can aim
  at the shoulder hit of A to reduce Black's moyo.
  <=
  ENDCOM
  ENDVAR
W 2 O14
COM
White escapes into the center with 2, ...
ENDCOM
B 3 P13
COM
... Black peeps with 3, then ...
ENDCOM
W 4 P14
B 5 M16
COM
... defends the territory at the top with 5. This is a basic
example of how to secure territory while attacking. White's stones
on the right are still vulnerable.
<=
ENDCOM