(;AB[sb]AB[rc]AB[rd]AB[pd]AB[pc]AB[nc]AB[nb]AW[rb]AW[pb]AW[pf]AW[qg]AW[rf]AW[nd]AW[ne]AW[mc]AW[mb]AW[kb]C[White to play. Black has a seemingly strong shape. Can it be killed?]AP[goproblems]
(;W[pa];B[qb];W[ra]
(;B[na];W[oc]C[];B[ob];W[od];B[qc];W[qa];B[sc];W[ma]C[RIGHT])
(;B[ob];W[na]C[RIGHT])
(;B[oa]
(;W[oc];B[od])
(;W[ob];B[oc];W[na]C[RIGHT])))
(;W[ra];B[ob])
(;W[qa];B[ob])
(;W[qb];B[ob])
(;W[ob];B[qb];W[ra];B[qa]))