(;
GM[1]
SZ[19]
AW[jc][nc][qc]
AB[dd][hc][lc][pd][pf]
LB[qc:1]
C[Problem 10. Black to play.  

This time White has switched to the corner with an invasion at 1. How should Black respond ? ]
;B[pc]
TE[2]
C[Correct Answer.  

Black should let White live in the corner and make a wall on the outside. ]
;W[pb]
(;B[ob];W[qb];B[oc];W[re]
C[White's two stones at the top are outnumbered, so Black should easily make profit there. <= ]
)
(;B[qd]
C[Variation.  

If the right side is important to Black, he could Black with 3. ]
;W[rb];B[rc];W[qb];B[kd]
C[Black ends with sente, so he can now switch to attacking the lone white stone at the center top with 7. <= ]
)
)