(;AB[aq]AB[bq]AB[br]AB[cr]AB[cp]AB[dp]AB[ep]AB[fp]AB[fr]AB[gq]AW[cq]AW[dq]AW[dr]AW[er]AW[es]AW[cs]AW[ap]AW[bp]AW[bo]AW[co]AW[do]TR[aq]TR[bq]TR[br]TR[cr]C[black to save his marked stones. NO KO!]AP[goproblems]
(;B[as];W[ds]
(;B[fs]C[RIGHT])
(;B[eq]C[RIGHT])
(;B[bs];W[ar]))
(;B[bs];W[as];B[ds]C[one-step ko for black.])
(;B[eq];W[bs])
(;B[fs];W[bs])
(;B[ar]C[dead in gote :(])
(;B[fq];W[bs]))