(;AB[cr]AB[dq]AB[eq]AB[er]AB[fr]AW[cq]AW[dp]AW[ep]AW[fp]AW[fq]AW[gr]AW[hq]AW[jq]AB[cn]AB[ck]C[tesuji to connect without ko]AP[goproblems]
(;B[cp];W[co]
(;B[bp];W[bo];B[bq])
(;B[bq];W[bo]
(;B[do];W[dn];B[eo];W[en];B[fo];W[fn];B[go];W[gn];B[ho];W[hn];B[io];W[in];B[jo]TR[cn]TR[ck]MA[dn]MA[en]MA[fn]MA[gn]MA[hn]MA[in]MA[fq]MA[hq]MA[jq]TR[go]TR[ho]TR[io]TR[fo]C[rectangulars are strong, triangulars are weak])
(;B[bn];W[dn])))
(;B[bp]
(;W[cp];B[bq]C[RIGHT])
(;W[bq];B[cp]
(;W[co];B[bo]C[RIGHT])
(;W[br]
(;B[aq];W[cs];B[dr];W[fs]C[B is dead])
(;B[ds];W[fs];B[bs];W[gs]
(;B[aq];W[es])
(;B[ar];W[es])
(;B[es]C[RIGHT])))))
(;B[bq];W[bp];B[cp];W[co];B[bo];W[cq]C[instruction : tesuji to connect without ko];B[ap];W[cp];B[bn];W[br];B[aq];W[cs];B[dr];W[fs]C[B is dead. B3 atari underneath is lead to ko.]))