EVENT
BOARDSIZE 19
SETUP W K17 M18 N17 O17 O18 
SETUP B D16 H17 L18 N18 M17 Q16 Q14 
MARK 2@N17 3@L18 1@N18 4@O18 B@R17 A@M16
COM
Problem 16. Black to play.  

The moves to 3 are normal, but instead of A, White ataries with
4, aiming to invade the corner at B. How should Black answer
? 

<See Reference Diagram 16 for White 4 at A.>
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B 1 Q18
USER
CORRECT ANSWER
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COM
Correct Answer.  

Defending the corner with 1 is best.  
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W 2 L17
COM
White next plays 2 and ...  
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B 3 M19
W 4 M16
B 5 K18
W 6 M18
B 7 J17
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... the moves to 7 are natural. Black has no reason to be dissatisfied.
<= 
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