(;AB[ap]AB[aq]AB[ar]AB[as]AB[fp]AB[fq]AB[fr]AW[eq]AW[dq]AW[cq]AW[bq]AW[cp]AW[co]AW[cn]AW[bn]AW[an]C[Black to connect the marked stones unconditionally.FORCE]TR[ap]TR[aq]TR[ar]TR[as]AP[goproblems]
(;B[cs];W[ds]C[FORCE]
(;B[dr]C[CHOICE]
(;W[er]C[FORCE]
(;B[es];W[cr]C[FORCE]
(;B[ds]C[Black is connected.RIGHT])
(;B[bs];W[ds]C[Ko.])
(;B[br];W[ds]C[Ko.])
(;B[fs];W[ds]C[Ko.]))
(;B[cr];W[es])
(;B[br];W[es])
(;B[bs];W[es]))
(;W[cr]C[FORCE]
(;B[es];W[er]C[FORCE]
(;B[ds]C[Black is connected.RIGHT])
(;B[bs];W[ds]C[Ko.])
(;B[br];W[ds]C[Ko.])
(;B[fs];W[ds]C[Ko.]))
(;B[bs];W[er])
(;B[er];W[bs])
(;B[br];W[er])))
(;B[cr];W[dr])
(;B[er];W[dr])
(;B[es];W[dr])
(;B[br];W[dr])
(;B[bs];W[dr]))
(;B[ds];W[cs]C[FORCE]
(;B[cr];W[es]C[FORCE]
(;B[bs];W[er])
(;B[er];W[dr])
(;B[dr];W[er])
(;B[br];W[er])
(;B[fs];W[er]))
(;B[bs];W[cr])
(;B[br];W[cr])
(;B[dr];W[cr])
(;B[es];W[cr])
(;B[er];W[cr]))
(;B[es];W[cs]C[FORCE]
(;B[er];W[cr])
(;B[ds];W[cr])
(;B[dr];W[cr])
(;B[cr];W[dr]C[FORCE]
(;B[ds];W[br])
(;B[br];W[ds])
(;B[bs];W[ds])
(;B[er];W[ds]))
(;B[bs];W[cr])
(;B[br];W[cr]))
(;B[bs]
(;W[ds]C[FORCE]
(;B[br];W[dr])
(;B[cr];W[dr])
(;B[cs];W[dr])
(;B[es];W[dr])
(;B[er];W[dr])
(;B[dr];W[er]C[FORCE]
(;B[cr];W[es])
(;B[cs];W[es])
(;B[br];W[es])
(;B[es];W[fs])))
(;W[dr]C[FORCE]
(;B[ds];W[es]C[FORCE]
(;B[er];W[cs])
(;B[cs];W[er])
(;B[cr];W[er])
(;B[br];W[er]))
(;B[cr];W[ds])
(;B[cs];W[ds])
(;B[br];W[ds])
(;B[es];W[ds])
(;B[er];W[ds])))
(;B[er];W[dr]
(;B[ds];W[cs]
(;B[es];W[cr])
(;B[cr];W[es])
(;B[br];W[es])
(;B[bs];W[es]))
(;B[es];W[ds])
(;B[cs];W[ds])
(;B[cr];W[ds])
(;B[br];W[ds])
(;B[bs];W[ds]))
(;B[dr];W[er]C[FORCE]
(;B[es];W[cs]C[FORCE]
(;B[cr];W[br]C[FORCE]
(;B[bs];W[ds])
(;B[ds];W[fs])
(;B[fs];W[ds]))
(;B[ds];W[cr])
(;B[bs];W[cr])
(;B[br];W[cr]))
(;B[ds];W[es])
(;B[cs];W[es])
(;B[cr];W[es])
(;B[br];W[es])
(;B[bs];W[es]))
(;B[cr];W[er]
(;B[dr];W[es])
(;B[ds];W[es])
(;B[cs];W[es])
(;B[bs];W[es])
(;B[br];W[es])
(;B[es];W[ds]
(;B[fs];W[dr])
(;B[cs];W[fs])
(;B[bs];W[fs])
(;B[br];W[fs])
(;B[dr];W[fs])))
(;B[br];W[er]C[FORCE]
(;B[dr];W[es])
(;B[ds];W[es])
(;B[cr];W[es])
(;B[cs];W[es])
(;B[es];W[ds]C[FORCE]
(;B[dr];W[fs])
(;B[cr];W[fs])
(;B[fs];W[dr])
(;B[cs];W[fs])
(;B[bs];W[fs]))
(;B[bs];W[es])))
stefliew