EVENT
BOARDSIZE 19
SETUP W D16 C17 D14 O17 D4 Q18 R18 R17 R16 R14 Q14 P13 Q12 
SETUP B D18 F17 F15 M17 Q16 P18 P17 Q17 Q15 Q4 R12 P14 O14 
MARK A@R12 B@Q14 C@P14 D@P13 E@O14 F@Q12
COM
Problem 104. Black to play.  

The position in the top left arose from a popular joseki. Black
attacked with A and the sequence continues to White F. How should
Black continue to press White ? 
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B 1 Q11
USER
CORRECT ANSWER
ENDUSER
COM
Correct Answer.

The hane of Black 1 is the correct continuation. Next, ...
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W 2 P11
COM
White 2 ...
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  VAR
  W 2 R11
  COM
  White might cut with 1, ...
  ENDCOM
  B 3 R10
  COM
  ... but Black plays 3 ...
  ENDCOM
  W 4 S11
  B 5 Q10
  COM
  ... and 5 in sente.
  ENDCOM
  W 6 S12
    VAR
    W 6 S10
    MARK @@S12
    COM
    Variation.

    Instead of 6 at @, Black should not turn at 6 here. If he does,
    ...
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    B 7 P12
    W 8 Q13
    B 9 O13
    COM
    ... Black 9 will become sente, ...
    ENDCOM
    W 10 S13
    B 11 F13
    MARK A@R8
    COM
    ... so Black can expand his moyo with 11, while attacking White's
    position an the left side. If Black later comes back to defend
    the lower right, the shape move is A.
    <=
    ENDCOM
    ENDVAR
  B 7 P12
  COM
  He then confines White's stones to the upper right with 7 ...
  ENDCOM
  W 8 R13
  B 9 O13
  COM
  ... and 9. This result is also good for Black.
  <=
  ENDCOM
  ENDVAR
  VAR
  W 2 O13
  COM
  If White pushes up with 2, ...
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  B 3 N13
  COM
  ... Black must hane at 3.
  ENDCOM
  W 4 N14
  COM
  White cuts with 4, ...
  ENDCOM
  B 5 O16
  W 6 P11
  B 7 Q10
  W 8 P10
  B 9 Q9
  W 10 P9
  MARK 8@P10 6@P11
  COM
  ... reinforces her stones with 6 to 10, ...
  ENDCOM
  B 11 Q8
  W 12 N15
  COM
  ... then switches to the top ...
  ENDCOM
  B 13 N16
  W 14 L14
  MARK A@M13
  COM
  ... with the sequence to 14. With all of his stones secure, Black
  can now fight by extending to A.
  <=
  ENDCOM
  ENDVAR
B 3 Q10
W 4 P10
COM
... and 4 are not good.
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B 5 Q9
MARK 3@Q10
COM
Black makes territory along the fourth line with 3 and 5, while
White gains nothing for her efforts.
<=
ENDCOM