EVENT
BOARDSIZE 19
SETUP W D16 K16 O17 D4 Q5 O5 R3 Q2 
SETUP B Q16 Q14 R9 Q3 F3 K4 O4 N5 R2 
MARK 1@O5 2@N5 3@R3 4@R2 5@Q2 \t@R9
COM
Problem 31. Black to play.  

Black has played the low Chinese opening with the marked stone.
How should Black respond to White 5 ? 
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B 1 Q4
MARK \t@R9
USER
CORRECT ANSWER
ENDUSER
COM
Correct Answer.

With the marked stone on the third line in place, bumping against
the white stone with Black 1 is the best move.
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W 2 R4
B 3 S2
W 4 R6
B 5 O3
MARK \t@R9 B@S9 A@Q9
COM
The sequence to Black 5 is now inevitable, and White's group
is still under attack.

Comparison.

If Black had played the high Chinese opening with the marked
stone at A, White could easily settle her group by sliding to
B.
<=
ENDCOM