This is a common corner shape, with many
complications.
(;AB[pr]AB[pq]AB[qq]AB[oq]AW[or]AW[nr]AW[nq]AW[kq]AW[pp]AW[qp]AW[op]AW[qn]C[Black to play]AP[goproblems]
(;B[rr]
(;W[rp]C[CHOICE];B[qs]C[Dipping down at 1 is the key. If White 2, Black makes two eyes with 3. RIGHT]LB[rr:1]LB[rp:2]LB[qs:3])
(;W[qs];B[rs];W[rp];B[ps];W[sr]))
(;B[rp];W[rr];B[rq];W[ro]))