(;AB[ar]AB[bs]AB[cr]AB[dr]AB[ds]AB[er]AW[es]AW[fs]AW[fr]AW[gr]AB[eq]AB[fq]AW[hq]AW[iq]AW[kq]AB[dp]AB[do]AB[eo]AB[hp]AB[ho]AB[go]AB[fp]AW[bq]AW[cq]AW[dq]AW[bo]AW[co]AW[dn]AW[en]AW[cm]AW[bm]AW[an]AB[dm]AW[fn]AW[ip]AW[io]AW[in]AW[hm]AB[gn]AW[gm]AB[aq]AB[ap]AB[kr]AB[lq]AW[kp]AB[lp]AB[lo]C[White to play. Can the corner black group be killed? Y = Yes, N = No, K = Ko.FORCE]LB[dk:Y]LB[fk:N]LB[hk:K]AP[goproblems]
(;W[dk];B[fk]C[Now proceed to kill.]
(;W[br];B[gq]
(;W[fo];B[hr]
(;W[is]
(;B[gs]
(;W[fs]
(;B[ir];W[jr];B[fr]
(;W[js];B[jq]
(;W[jp];B[ks]
(;W[jq];B[es];W[hs]C[RIGHT])
(;W[lr];B[es]LB[hs:A]C[Uh oh, white cannot approach at A.]))
(;W[lr];B[es]C[Uh oh, white cannot approach at A.]LB[hs:A]))
(;W[lr];B[es])
(;W[jq];B[es]))
(;B[fr];W[ir];B[es];W[hs]C[RIGHT]))
(;W[ir];B[fs])
(;W[jr];B[fs])
(;W[fr];B[fs])
(;W[gr];B[hs])
(;W[hs];B[ir]))
(;B[hs];W[ir];B[gs];W[fs]C[RIGHT])
(;B[ir];W[jr];B[gs];W[fs]C[This transposes back to the main line.RIGHT];B[fr]
(;W[js];B[jq]
(;W[jp];B[ks]
(;W[jq];B[es];W[hs]C[RIGHT])
(;W[lr];B[es]LB[hs:A]C[Uh oh, white cannot approach at A.]))
(;W[lr];B[es]C[Uh oh, white cannot approach at A.]LB[hs:A]))
(;W[lr];B[es])
(;W[jq];B[es])))
(;W[ir];B[gs]
(;W[fs];B[is]
(;W[js];B[jr])
(;W[jr];B[fr];W[js];B[es])
(;W[fr];B[jr]))
(;W[is];B[fs])
(;W[fr];B[fs])
(;W[jr];B[fs])
(;W[js];B[fs]))
(;W[jr];B[gs])
(;W[hs];B[gs];W[ir];B[is];W[js];B[fs]))
(;W[hr];B[fo])
(;W[ir];B[fo])
(;W[hs];B[fo]))
(;W[gq];B[br])
(;W[fo];B[br]))
(;W[fk])
(;W[hk]))