(;SZ[19]AW[bl]AW[cl]AW[cm]AW[dn]AW[en]AW[bo]AW[eo]AW[bp]AW[cp]AW[fp]AW[gp]AW[bq]AW[gq]AW[br]AW[dr]AW[fr]AW[ir]AW[es]AW[fs]AB[bm]AB[an]AB[bn]AB[cn]AB[ao]AB[co]AB[do]AB[dp]AB[aq]AB[cq]AB[eq]AB[fq]AB[cr]AB[er]AB[as]C[White to play - can he kill the black stones?]GM[1]FF[4]CA[UTF-8]AP[CGoban:2]ST[2]RU[Japanese]KM[0.00]PW[Weiß]PB[Schwarz]PL[W]
(;W[bs]
(;B[cs]C[CHOICE]
(;W[dq];B[ds];W[dq];B[dr]
(;W[ep];B[dq]
(;W[ar];B[gr];W[ap];B[gs];W[fs]C[Black is dead! RIGHT])
(;W[gr];B[ap]))
(;W[ar];B[ap]))
(;W[ds];B[dq]
(;W[ar];B[ap]C[Black lives])
(;W[ep];B[ap]C[Black lives])
(;W[gr];B[ap])))
(;B[dq];W[ap]C[Black is deadRIGHT]))
(;W[cs];B[dq]
(;W[bs]C[Ko, but this is not good enough...])
(;W[ds];B[bs]
(;W[ar];B[bs]
(;W[as];B[ap]C[Black lives])
(;W[ap];B[gr];W[as];B[gs]C[Black lives]))
(;W[gr];B[ap];W[ar];B[bs]C[Black lives])
(;W[hr];B[ap];W[ar];B[bs]C[Black lives]))
(;W[ap];B[ds];W[ar];B[bs];W[cs];B[bs];W[gr];B[cs]))
(;W[ar];B[cs];W[dq];B[ds];W[dq];B[ap]C[Black lives])
(;W[ds];B[dq]
(;W[cs];B[bs]
(;W[ar];B[bs]
(;W[as];B[ap]C[Black lives])
(;W[ap];B[gr];W[as];B[gs]C[Black lives]))
(;W[gr];B[ap];W[ar];B[bs]C[Black lives])
(;W[hr];B[ap];W[ar];B[bs]C[Black lives]))
(;W[bs])))