EVENT
BOARDSIZE 19
SETUP W D17 C16 C15 D3 
SETUP B C14 D15 Q4 Q16 
MARK \t@D17 \t@D3 4@C16 2@C15 3@C14 1@D15
COM
Problem 33. Black to play.  

This time Black encounters White's mukai-komoku formation (the
marked stones) with a high approach move at 1. After exchanging
3 for 4, what should Black do ? 
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B 1 D5
USER
CORRECT ANSWER
ENDUSER
COM
Correct Answer.

Black should play another high approach move with 1.
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W 2 D14
COM
It would be natural for White to cut at 2, but ...
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  VAR
  W 2 C5
  COM
  Variation.

  White could also attach at 2.
  ENDCOM
  B 3 C6
  W 4 C4
  B 5 D14
  W 6 F17
  B 7 D6
  W 8 F3
  COM
  The sequence to White 8 would then be the natural flow.
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  B 9 D10
  COM
  However, Black 9 becomes an excellent move, making an ideal extension
  from his stones at the top and the bottom.
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  W 10 R10
  COM
  White would then play 10 on the right side.
  ENDCOM
  B 11 R8
  W 12 R13
  B 13 R15
  W 14 N17
  B 15 P17
  W 16 O3
  B 17 Q3
  W 18 L4
  COM
  The sequence to 18 is from a game between Takagawa (Black) and
  Sakata.
  <=
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  ENDVAR
  VAR
  W 2 F4
  MARK 1@D5 A@C7
  COM
  Variation.

  White could also respond to Black 1 with 2 or a pincer at A.
  <=
  ENDCOM
  ENDVAR
B 3 F4
COM
... then 3 would give Black wonderful influence in the center
which combines well with his niren-sei formation on the right.
<=
ENDCOM