(;
GM[1]
SZ[19]
AW[jc][nd]
AB[dd][fc][pe][qc][qj]
C[Problem 11. Black to play.  

Again White has a three-space high extension, but the neighbouring black stones are on different points. How should Black play ?  

<See Reference Diagram 11 for 'White to move' in the upper right.> ]
;B[lc]
TE[2]
C[Correct Answer.  

Black should make a deep invasion with 1. ]
;W[ld]
C[This time, when White attaches with 2, ... ]
;B[mc]
C[... Black simply extends to 3, ... ]
;W[md];B[ob]
C[... then jumps lightly to 5. ]
;W[kc]
C[White must complete her shape with 6, so Black ends in sente. <= ]
)
)