EVENT
BOARDSIZE 19
SETUP W D16 D10 C4 E3 R10 R7 
SETUP B Q4 R5 N3 R12 R16 P17 
COM
Problem 6. Black to play.  

This is a continuation of the "Correct Answer of Problem 2".
How should Black attack the two white stones on the right side
? 
ENDCOM
B 1 P10
USER
CORRECT ANSWER
ENDUSER
COM
Correct Answer.  

Capping with Black 1 is the key point.  
ENDCOM
W 2 Q11
COM
If White runs away with 2, ...  
ENDCOM
  VAR
  W 2 P7
  MARK @@Q11
  COM
  Variation.  

  Instead of @ in the Correct Answer, White might jump to 2 here.
  ENDCOM
  B 3 S9
  COM
  Black again gouges out White's base by playing 3 ...  
  ENDCOM
  W 4 R9
  B 5 S8
  COM
  ... and 5.  
  ENDCOM
  W 6 P9
  MARK B@S7 A@S10
  COM
  White attaches with 6, but his stones are still eyeless, while
  the black stones at the edge can link up to their allies above
  or below with A or B.
  <=
  ENDCOM
  ENDVAR
B 3 S9
W 4 R9
  VAR
  W 4 S10
  COM
  Variation.  

  White could block at 4, but ...  
  ENDCOM
  B 5 R9
    VAR
    B 5 R8
    MARK @@R9
    COM
    Variation.  

    Instead of @ in Variations 1 and 2, ...  
    ENDCOM
    W 6 Q8
    B 7 S7
    COM
    ... Black could link up his stones to the bottom with the sequence
    to 7, but this strategy is a bit weak-spirited.  <= 
    ENDCOM
    ENDVAR
  W 6 Q10
    VAR
    W 6 Q9
    COM
    Variation.  

    White could establish a position in the lower right by blocking
    at 6.  
    ENDCOM
    B 7 Q10
    W 8 R8
    B 9 P9
    W 10 Q8
    B 11 R11
    W 12 S8
    B 13 S11
    COM
    With the sequence to 13, Black sacrifices two stones and builds
    a moyo in the upper right.  
    ENDCOM
    W 14 T9
    B 15 P12
    MARK A@S6 \t@Q11
    COM
    To secure his moyo, he must capture the marked stone by playing
    at 15, but he might first want to rob the white stones of their
    second eye by playing at A.  <= 
    ENDCOM
    ENDVAR
  B 7 Q9
  W 8 P9
  B 9 P8
  W 10 O9
  B 11 Q7
  COM
  ... with the sequence to 11, Black has secured the territory
  in the lower right.  
  ENDCOM
  W 12 O11
  COM
  White still has to play 12 to secure her stones, so Black ends
  in sente.  <= 
  ENDCOM
  ENDVAR
B 5 S8
W 6 R8
B 7 S7
COM
... Black will gauge out White's base with the sequence to 7.
White's stones are now floating in the center, providing an easy
target to attack.  <= 
ENDCOM