(;AW[qa]AW[ob]AW[nc]AW[pc]AW[od]AW[qd]AW[re]AB[pb]AB[rb]AB[qc]AB[sc]C[Black to live]AW[rf]
(;B[rd];W[qb]
(;B[qe];W[pd])
(;B[ra];W[pa]))
(;B[pa];W[rd]
(;B[ra];W[rc]
(;B[qb];W[sb])
(;B[sb];W[qb]))
(;B[rc];W[ra]
(;B[sa];W[sb]
(;B[qb]C[RIGHT])
(;B[sa]C[This move is forbidden by the ko rule!])
(;B[oa];W[na]
(;B[sa]C[];W[qb])
(;B[qb];W[sd]))
(;B[na];W[oa]
(;B[sa];W[qb])
(;B[qb];W[sd]))
(;B[pd]C[NOTTHIS]))
(;B[qb];W[sa]))
(;B[sa];W[rc])
(;B[qb];W[rc]C[Black cannot get two eyes.]))
(;B[qb];W[pa]
(;B[rd];W[ra])
(;B[ra];W[rd];B[oa];W[pa]))
(;B[ra];W[rd];B[pa];W[rc]
(;B[qb];W[sb])
(;B[sb];W[qb])))