(;AB[dd]AB[bd]AB[ce]AB[fd]AB[hd]AB[gd]AB[gc]AW[be]AW[bf]AW[cf]AW[df]AW[dh]AW[gg]AW[he]AW[jd]AW[id]AW[hc]AW[ib]AW[kc]AW[kb]AB[jc]AW[fg]AW[bc]LB[bc:A]C[How can Black best respond to A?]AP[goproblems]
(;B[cc];W[ad]
(;B[bb];W[cd]C[]
(;B[db]C[Good.RIGHT])
(;B[dc])
(;B[cb])
(;B[ec])
(;B[ed])
(;B[de]))
(;B[cd];W[bb]C[B is too cramped.])
(;B[dc];W[bb]C[B does not have enough space.]))
(;B[ad];W[ec]
(;B[cd];W[gb]
(;B[dc];W[fb]
(;B[bb];W[ed]C[B lives, but loses four stones. B can do better.])
(;B[cb];W[bb])
(;B[db];W[bb])
(;B[ed];W[db]))
(;B[fb];W[eb]C[B must cut W when the opportunity presents itself.])
(;B[cc]C[Not enough space.]))
(;B[hb];W[cc]C[B allowed W to connect his stones.])
(;B[gb];W[cc]C[B allowed W to connect his stones.])
(;B[fb];W[cc]C[B allowed W to connect his stones.])
(;B[ed];W[dc]C[B allowed W to connect.])
(;B[dc]C[D17 is the best way to deal with the mistake of A16.];W[gb]C[B will live, but this is not the best B could do. (I don't know all the variations here.)]))
(;B[hb];W[ad];B[ic];W[jb]C[B got nothing from H18.])
(;B[dc];W[cc]C[D17 is too early.];B[ad];W[cd]
(;B[de];W[ac])
(;B[cb]
(;W[ac]C[Very bad for Black.])
(;W[bb]))
(;B[hb];W[ic];B[cb];W[bb]))
(;B[cd];W[ad];B[cc];W[bb]C[B is in a lot of trouble.]))