(;AB[dp]AB[dq]AB[dr]AB[ds]AB[er]AW[fr]AW[fq]AW[eq]AW[ep]AW[cs]AW[cr]AW[co]AW[eo]AW[bp]AB[gr]AB[gq]AB[gp]AW[bq]AW[br]TR[ds]TR[dr]TR[er]TR[dq]TR[dp]C[Black has one big external ko threat. Save the marked stones.]AW[gs]AB[hr]AP[goproblems]
(;B[fs];W[es]C[White takes the ko. You have one big ko threat at A (J4) that White will probably answer, maybe not. Only play A if you need it to survive.]LB[ip:A]
(;B[ip];W[iq]C[White answered the ko threat...]
(;B[fs];W[do]C[]
(;B[hs];W[cp]
(;B[gs];W[cq];B[es]C[Good!RIGHT])
(;B[es];W[cq];B[gs]C[Good but playing G1 first gives less of a ko threat for whiteRIGHT]))
(;B[es];W[cp];B[hs];W[cq];B[gs]C[Good but playing G1 first gives less of a ko threat for whiteRIGHT]))
(;B[hs];W[fs])
(;B[do];W[dn];B[fs];W[cp];B[hs];W[cq]C[Awww.]))
(;B[do];W[dn];B[fs];W[cp];B[hs];W[cq]C[You won the ko, but lost a liberty... You did need the external threat at A after all.])
(;B[dn];W[do];B[fs];W[cp];B[hs];W[cq]C[You won the ko, but lost a liberty... You did need the external threat at A after all.]))
(;B[do];W[dn]
(;B[cp];W[bn])
(;B[cq];W[fs])
(;B[fs];W[cp];B[hs];W[cq]C[You won the ko, but lost a liberty...])
(;B[en];W[cp]
(;B[fs];W[cq]C[])
(;B[cn];W[dm];B[fs];W[cq]C[])
(;B[fo];W[cq]))
(;B[cn];W[cp]
(;B[en];W[dm];B[fs];W[cq]C[])
(;B[fs];W[cq])))
(;B[dn];W[do];B[fs];W[cp];B[hs];W[cq]))