(;GM[1]FF[4]CA[UTF-8]AP[CGoban:3]ST[2]
RU[Japanese]SZ[19]KM[0.00]
PW[White]PB[Black]AW[ra][fb][nb][rb][dc][ec][fc][oc][pc][qc][bd][cd][dd][qo][bp][pp][rp][bq][cq][dq][mq][nq][oq][pq][rq][dr][er][mr]AB[ea][db][eb][sb][ac][bc][cc][jc][lc][mc][nc][rc][nd][od][pd][qd][rd][bm][bo][co][cp][dp][ep][eq][fq][qq][sq][fr][hr][nr][or][pr][rr]LB[ji:1][jj:2][jk:3][jl:4]C[
1. upper right: black to play
2. lower right: black to play
3. lower left: black to play
4. upper left: white to play]
(;B[ji]
;W[me]
(;B[pb]
(;W[pa]
;B[oa]
;W[qb]
;B[qa]C[Ko]
;W[ob]TR[jc][lc]C[If the marked stones weren't on the board: ]
;B[pa]
;W[na]
;B[pa]TR[jc][lc]C[The white group is dead,  the marked stones keeps the white group from escaping. ])
(;W[qb]
;B[pa]
;W[mb]
;B[lb]
;W[ma]
;B[oa]C[dead])
(;W[ob]
;B[pa]
;W[mb]
;B[lb]
;W[ma]
;B[oa]C[dead]))
(;B[na]
;W[mb]
;B[ob]
;W[pb]
;B[pa]
;W[oa]C[ko])
(;B[pa]
;W[pb]
;B[oa]
;W[qa]C[white lives]))
(;B[jj]
;W[oo]
(;B[qs]TR[ps][rs]C[two eyes])
(;B[ns]
;W[sr]
;B[ss]
;W[qs]
;B[ps]
;W[qr]
;B[rs]
;W[qr]C[dead]))
(;B[jk]
;W[fo]
(;B[es]
(;W[bs]
;B[ar]
;W[br]TR[ar][cr]C[Alive])
(;W[br]
;B[cs]
;W[ds]
;B[bs]
;W[ap]
;B[ar]C[Seki]))
(;B[ap]
(;W[br]
;B[cs]
;W[bs])
(;W[bs]
;B[ar]
;W[aq]
;B[br]
(;W[cr]
;B[es]
;W[ds]
;B[cs]C[oops :-)])
(;W[es]
;B[cs]
;W[cr]C[alive :-)])))
(;B[br]
;W[ar]
;B[cs]
;W[cr]
;B[bs]
;W[ap]C[Alive])
(;B[bs]
;W[ar]
;B[ap]
;W[cs]
;B[es]
;W[br])
(;B[cs]
;W[ar]
;B[br]
;W[cr]))
(;B[jl]
;W[ca]
(;B[ba]
;W[bb]
;B[ab]
;W[aa])
(;B[bb]
;W[ba]
;B[aa]C[ko])))
