(;GM[1]FF[4]CA[UTF-8]AP[CGoban:3]ST[2]
RU[Japanese]SZ[19]KM[0.00]
PB[Black to play and kill]AW[ln][mn][pn][no][po][qo][lp][mp][qp][nq][oq][pq][rq][qr][rr]AB[lm][mm][pm][qm][kn][nn][on][qn][rn][ko][ro][kp][rp][sp][lq][mq][nr][or][pr][ps]
;B[op]C[This is the first move.]
;W[oo]
;B[np]C[This move and the next threaten a snap-back shape.]
;W[pp]
;B[np]
(;W[mo]
(;B[rs]C[This is the trick for ensuring there is no eye in the corner.]
;W[qs]
;B[sr]
;W[ss]
;B[sq]C[White is dead.])
(;B[qs]C[Just pushing is no good as white makes a second eye.]
;W[rs]
;B[sq]
;W[sr]C[White lives.]))
(;W[qs]
;B[mo]C[White is now caught in a snap-back or a straight capture.]
(;W[sq]
;B[ss]C[This is still dead])
(;W[lo]
;B[mo])
(;W[op]
;B[lo])))
