(;AB[ra]AW[rc]AB[jd]AB[je]AB[jc]AB[kd]AB[kb]AW[kc]AW[lc]AW[ld]AW[md]AW[nd]AB[le]AB[me]AB[ne]AB[oe]AB[od]AB[pd]AB[pc]AB[qc]AB[pb]AW[qb]AW[qa]AW[pa]AW[ob]AW[oc]AW[ke]AW[kf]AW[lf]AW[mf]AW[og]AW[pf]AW[qe]AW[qd]AW[sb]AB[hc]AB[fc]C[So...How do you save the marked stones?]MA[pb]MA[pc]MA[qc]MA[pd]MA[od]MA[oe]MA[ne]MA[me]MA[le]AP[goproblems] (;B[nc] (;W[lb] (;B[mb];W[la] (;B[ma];W[jb]C[:S]) (;B[oa];W[na]C[:S]) (;B[na];W[oa] (;B[ka];W[jb]C[:S]) (;B[nb];W[rb]C[:S - Can't approach from inside but it isn't seki - White can take P15.]) (;B[jb];W[ma]C[:S]) (;B[ja];W[ma]C[:S]) (;B[ma];W[jb]C[:S]) (;B[mc];W[jb]C[:S])) (;B[jb];W[ma]C[:S]) (;B[ja];W[ma]C[:S]) (;B[ka];W[jb]C[:S])) (;B[nb];W[oa] (;B[mb];W[ma]C[:S]) (;B[ma];W[nf]C[:S]) (;B[la];W[jb] (;B[ka];W[ma] (;B[na];W[rb];B[mb]C[Well done! ;)RIGHT]) (;B[mb];W[ja]C[:S])) (;B[ma];W[ka]C[:S]) (;B[mb];W[ka]C[:S]) (;B[na];W[rb] (;B[ka];W[ja];B[ma];W[gg]C[White tenukies and still wins. (However black also saves M19)]) (;B[ja];W[ka]C[Not good enough]MA[kb]) (;B[ma];W[ka]C[:S]) (;B[mb];W[ka]C[:S]) (;B[mc];W[ka]C[:S]) (;B[ib];W[ka]C[:S])) (;B[ib];W[ka]C[:S]) (;B[ja];W[ka]MA[kb]C[Not good enough.])) (;B[na];W[rb] (;B[la];W[jb] (;B[ka];W[ja];B[ma];W[gg]C[White tenukies and still wins. (However black also saves M19)]) (;B[ja];W[ka]C[Not good enough.]MA[kb]) (;B[ma];W[ka]C[:S]) (;B[mb];W[ka]C[:S]) (;B[mc];W[ka]C[:S])) (;B[jb];W[nf]C[:S]) (;B[ka];W[la]C[:S]) (;B[ja];W[la]C[:S])) (;B[ka];W[la]C[:S]) (;B[jb];W[la]C[:S]) (;B[ja];W[la]C[:S])) (;B[oa];W[na] (;B[nb];W[oa] (;B[ma];W[rb] (;B[la];W[jb];B[ka];W[ja]C[:S]) (;B[ka];W[la]C[:S]) (;B[mb];W[jb]C[:S]) (;B[jb];W[la]C[:S]) (;B[ja];W[la]C[:S])) (;B[mb];W[ma]C[:S]) (;B[la];W[mb]C[:S]) (;B[ka];W[la]C[:S]) (;B[jb];W[la]C[:S]) (;B[ja];W[la]C[:S])) (;B[mb];W[ma]C[:S]) (;B[la];W[mb]C[:S]) (;B[ma];W[la]C[:S] (;B[mb];W[jb]C[:S]) (;B[nb];W[mb]C[];B[oa];W[ob]C[:S])) (;B[jb];W[la]C[:S]) (;B[ja];W[la]C[:S]) (;B[ka];W[la]C[:S])) (;B[na];W[nb] (;B[la]C[:S (Double ko/Life for white..Black dead either way)]) (;B[mb];W[mc];B[la];W[ma]MA[mb]C[Not good enough.]) (;B[ma];W[la]C[:S]) (;B[jb];W[la]C[:S]) (;B[ka];W[la]C[:S]) (;B[ja];W[la]C[:S])) (;B[ma];W[la] (;B[mb];W[jb]C[:S]) (;B[mc];W[jb]C[:S]) (;B[jb];W[nf]C[:S]) (;B[ja];W[nf]C[:S]) (;B[nb];W[oa] (;B[jb];W[nf]C[:S]) (;B[ka];W[jb]C[:S]) (;B[ja];W[nf]C[:S]) (;B[mb];W[jb]C[:S]) (;B[na];W[rb] (;B[jb];W[nf]C[:S]) (;B[ka];W[jb]C[:S]) (;B[ja];W[nf]C[:S]))) (;B[oa];W[na] (;B[mb];W[jb]C[:S]) (;B[nb];W[mb]C[];B[oa];W[ob]C[:S])) (;B[na];W[oa] (;B[mb];W[jb]C[:S]) (;B[mc];W[jb]C[:S]) (;B[nb];W[rb] (;B[jb];W[nf]C[:S]) (;B[ka];W[jb]C[:S]) (;B[ja];W[nf]C[:S])))) (;B[la]C[The correct white response is N18.]TR[mb] (;W[mb] (;B[nb];W[na] (;B[oa];W[ob] (;B[jb];W[oa]C[:S]) (;B[oc];W[jb];B[oa]C[Ko..]MA[ob]) (;B[ka];W[ma]C[:S])) (;B[jb];W[mc]C[:S])) (;B[ma];W[na]C[:S]) (;B[jb];W[ma]C[:S])) (;W[ma];B[nb] (;W[oa];B[na] (;W[rb];B[mb]C[:S]) (;W[ka];B[rb]C[:S])) (;W[ka];B[oa];W[rb];B[jb]C[:S])) (;W[nb];B[mb]C[:S]) (;W[na];B[mb]C[:S])) (;B[ka];W[nf]C[:S]) (;B[ja];W[nf]C[:S]) (;B[jb];W[nf]C[:S])) (;W[mb];B[nb] (;W[oa];B[lb]C[:S]) (;W[nf];B[lb]C[:S]) (;W[lb];B[oa]C[:S])) (;W[nb];B[lb];W[mc];B[mb];W[nc];B[na]C[:S]) (;W[mc];B[nb] (;W[oa];B[mb]C[:S]) (;W[mb];B[oa]C[:S]))) (;B[nb];W[nc]C[:S]) (;B[mb];W[nc]C[:S]) (;B[lb];W[mb]C[:S]) (;B[mc];W[mb]C[:S]) (;B[nf];W[ng]C[:S]) (;B[of]C[:S]) (;B[pe]C[:S]) (;B[jb];W[lb]C[:S]) (;B[na];W[nb] (;B[ma];W[mb] (;B[la];W[oa]C[:S]) (;B[oa];W[la]C[:S])) (;B[oa];W[ma]C[:S]) (;B[mb];W[nc]C[:S])) (;B[ma];W[lb] (;B[na];W[oa]C[:S]) (;B[nc];W[nf]C[:S]) (;B[la];W[mb]C[:S]) (;B[mb];W[nf]C[:S]) (;B[nb];W[oa]C[:S])) (;B[la];W[mb]C[:S]))