(;SZ[19]AW[ho]AW[io]AW[jo]AW[no]AW[gp]AW[hp]AW[kp]AW[pp]AW[fq]AW[hq]AW[jq]AW[kq]AW[nq]AW[fr]AW[gr]AW[kr]AW[mr]AW[es]AW[fs]AW[ls]AB[gn]AB[hn]AB[in]AB[jn]AB[qn]AB[go]AB[ko]AB[lo]AB[ep]AB[fp]AB[jp]AB[lp]AB[eq]AB[iq]AB[lq]AB[cr]AB[er]AB[hr]AB[lr]AB[ds]C[Black to play. There is kosumi-tesuji here]GM[1]FF[4]CA[UTF-8]AP[CGoban:3]ST[2]RU[Japanese]KM[0.00]PW[sai]PB[toya koyo](;B[is];W[ip](;B[gs]C[Correct. Ko is the best you can doRIGHT])(;B[ir];W[jp]C[Not this way])(;B[hs];W[js]C[damezumari (you can't play at 'a')]LB[gs:a]))(;B[hs];W[ir]LB[gs:a]C[damezumari (you can't play at 'a')])(;B[jr];W[ip];B[is];W[gq](;B[ks];W[js]C[White is alive with double ko.])(;B[gs];W[ir]C[White lives with double ko.]))(;B[ir];W[ip];B[is]))