(;AB[fs]AB[gs]AB[gr]AB[gq]AB[gp]AB[go]AB[fn]AB[en]AB[dn]AB[co]AB[cp]AB[bn]AW[cq]AW[do]AW[eo]AW[fo]AW[fp]AW[fq]AW[fr]AW[es]AW[eq]C[How can black kill unconditionally?]AP[goproblems]
(;B[dr]C[]
(;W[cr]
(;B[dp];W[dq];B[ar];W[bp]C[]
(;B[ap]C[Well done! So strong!!RIGHT])
(;B[bq];W[br];B[ap];W[aq]C[This is ko. Not good enough sorry.]))
(;B[dq];W[dp];B[ds];W[cs];B[er];W[es])
(;B[er]
(;W[dp];B[ds];W[cs];B[bq];W[br];B[ar];W[bp];B[ap]C[This is ko. There is better.])
(;W[dq]
(;B[bq];W[br]
(;B[bp];W[ds])
(;B[ds];W[bp]))
(;B[ds];W[dp];B[bq];W[br];B[ar];W[bp];B[ap]C[This is ko. There is better.]))))
(;W[dq]
(;B[dp];W[bp]
(;B[ap];W[aq];B[br];W[cr];B[bq];W[ao];B[cs];W[ar];B[bs]C[Well done! So strong!!RIGHT])
(;B[br];W[bq]
(;B[er];W[cr];B[ds];W[cs];B[es];W[ar])
(;B[cr];W[er];B[ap];W[aq]
(;B[ao];W[bs])
(;B[bs];W[cs];B[ao];W[ar];B[bo];W[ds]))))
(;B[ar];W[bq];B[dp];W[br];B[er];W[cr];B[ds];W[cs];B[es]C[];W[as]C[You failed sorry.])
(;B[cr];W[br];B[bs];W[aq];B[er];W[as]C[This is ko, there is better.])))
(;B[dq];W[dp]
(;B[dr];W[cr];B[ds];W[cs];B[er];W[es])
(;B[cr];W[dr];B[bq];W[dq]))
(;B[dp];W[br]
(;B[dq];W[dr];B[bq];W[cr];B[ar];W[bp];B[ap]C[This is ko. There is better.])
(;B[dr];W[dq]
(;B[er];W[cs];B[ds];W[bp])
(;B[bp];W[cs])
(;B[cs];W[cr];B[ds];W[bs]))))