(;AP[goproblems]AW[aq]AW[bq]AW[cq]AW[dq]AW[er]AW[eq]AB[es]AB[dr]AB[cr]AB[cs]AW[br]AB[fr]AB[gr]AB[hq]AB[iq]AW[fq]AW[gq]AW[hp]AW[ip]AB[jq]AB[jp]AW[gp]AB[io]AB[ho]AB[go]AB[jo]AB[fo]AB[do]AB[bo]LB[br:1]C[white plays 1. what should black do?](;B[bs];W[fs](;B[hr](;W[ds]C[white can start a double-ko for unconditional life])(;W[as]))(;B[gs];W[ar]C[white should just play ko at A1. this is a trick move.](;B[hr];W[as](;B[ds];W[fs](;B[ds];W[cs];B[es];W[dr])(;B[cs];W[ds];B[cr]C[RIGHT])(;B[es];W[cs]))(;B[fs];W[ds];B[cs];W[cr]C[ko is not best here]))(;B[hs];W[as];B[ds];W[fs];B[cs]C[this leaves an extra ko threat at J1])(;B[ir];W[as];B[ds];W[fs];B[cs]C[this leaves two extra ko threats at H2])(;B[is];W[as];B[ds];W[fs];B[cs]C[this leaves extra ko threats])(;B[ds];W[as](;B[hr];W[fs];B[cs];W[ds];B[cr]C[RIGHT])(;B[hs];W[fs];B[cs]C[this leaves extra ko threats])(;B[ir];W[fs];B[cs]C[this leaves extra ko threats])(;B[is]C[this leaves extra ko threats];W[fs];B[cs]C[this leaves extra ko threats]))(;B[fs];W[as](;B[ds];W[hr])(;B[hr];W[ds];B[cs];W[cr]C[ko not best here])))(;B[ds];W[as]))(;B[fs];W[bs](;B[ds];W[hr])(;B[hr];W[ds]))(;B[ds];W[bs](;B[fs];W[hr])(;B[hr];W[fs]))(;B[gs];W[bs])(;B[hr];W[bs](;B[ds];W[fs])(;B[fs];W[ds]))(;B[as];W[bs])(;B[cp];W[bs])(;B[bp];W[bs])(;B[ap];W[bs])(;B[co];W[bs])(;B[eo];W[bs])(;B[dp];W[bs])(;B[ep];W[bs])(;B[fp];W[bs]))
adum