EVENT
BOARDSIZE 19
SETUP W D16 D4 K4 N4 R11 R14 Q14 
SETUP B Q3 Q9 S10 R15 Q16 O16 K16 
MARK 1@N4
COM
Problem 86. Black to play.  

Suppose White doesn't defend her stones in the upper right and
extends to 1 at the bottom instead. How should Black continue
? 
ENDCOM
B 1 P11
USER
CORRECT ANSWER
ENDUSER
COM
Correct Answer.

The cap of Black 1 keeps up the pressure on White.
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  VAR
  B 1 P4
  USER
  CORRECT ANSWER
  ENDUSER
  COM
  Correct Answer.

  It is also possible for Black to simply defend with the diagonal
  move of 1 and wait to see how White will play at the top.
  <=
  ENDCOM
  ENDVAR
W 2 S11
B 3 R10
W 4 Q11
B 5 P10
W 6 P12
B 7 O12
W 8 P13
COM
After White 8, ...
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B 9 P4
COM
... Black can defend his territory in the lower right with 9.
<=
ENDCOM