(;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?]AP[goproblems]
(;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]))