(;GM[1]FF[4]CA[UTF-8]SZ[19]AB[bd][bc][cc][dc][db][ea][ae][sc][rc][qc][pc][oc][nc][mc][lb][kc][rq][qq][pq][oq][or][bm][cm][cn][do][dp][dq][dr][cr][ap]AW[eb][fb][ec][ed][dd][cd][ce][be][bg][sb][rb][qb][pb][ob][rp][qp][pp][op][np][nq][nr][rn][sp][br][cq][cp][co][bn][an]TR[jj]C[1: lower left
2: upper left
3: upper right
4:lower right](;B[ji]C[lower left, white to play];W[bp](;B[aq](;W[bq];B[am];W[ar])(;W[ar]C[error];B[ao];W[bs];B[am];W[bo];B[bq]C[oops]))(;B[ar];W[ao];B[bs];W[bq]C[don't make a ko!]TR[aq]))(;B[jj]C[Upper left, white to play](;W[ba];B[ad](;W[ca];B[da];W[ab];B[bb]C[Seki])(;W[fa];B[da];W[bb];B[ab];W[aa]C[10.000 year ko :-)]))(;W[bb];B[ab];W[ba];B[ad])(;W[ca];B[da];W[bb];B[ab];W[ad];B[ba];W[aa];B[cb];W[ac];B[ab];W[ac];B[ad];W[af];B[ab]C[black is alive in double ko]))(;B[jk]C[upper right, black to play];W[tt];B[ra](;W[qa];B[oa](;W[nb];B[na];W[mb];B[ma])(;W[na];B[nb]))(;W[nb](;B[na];W[oa];B[qa];W[mb];B[ma];W[la];B[ma])(;B[qa];W[na];B[pa]C[Seki ])))(;B[jl]C[lower right, white to play](;W[ps];B[os];W[sq];B[sr];W[rr];B[rs];W[qr])(;W[sq];B[sr](;W[rs](;B[rr];W[ps];B[os];W[qr]C[dead])(;B[qr];W[os];B[ps];W[rr]))(;W[rr];B[rs];W[ss]C[failure, KO]))))