(;GM[1]FF[4]CA[UTF-8]AP[CGoban:3]ST[2]
RU[Japanese]SZ[19]KM[0.00]
GN[ ]PW[ ]PB[Black to play and kill]AW[nq][oq][pq][qq][rq][or][ps]AB[mo][oo][qo][np][rp][mq][mr][ns][os]FG[259:]PM[2]
(;B[rs]C[If Black starts here, then White can live by fighting and winning a ko.]
;W[qr]
;B[qs]
;W[rr]
;B[pr])
(;B[sq]C[The hane often works.]
;W[sr]
(;B[qr]
;W[rs]C[This way White lives.])
(;B[rs]
;W[qr]C[This is the ko shape again.]
(;B[rr]C[If Black tries this...]
;W[qs]C[This is two eyes, as Black's two stones are trapped.])
(;B[qs]C[This is the ko line.]
(;W[rr]
;B[pr])
(;W[pr]C[To connect is just dead.])))
(;B[rr]
;W[sp]
(;B[qs]C[This looks like a ko but isn't.]
;W[qr]
;B[pr]
;W[rs])
(;B[qr]
;W[rs]
;B[qs]
;W[pr])
(;B[rs]
;W[qr]
;B[qs]
;W[ss])))
(;B[qr]C[This is the play that kills cleanly.]
;W[rr]
;B[sq]C[If Black plays hane now....]
;W[sr]C[... even if White blocks...]
;B[rs]C[... Black plays this way and threatens to make a killing shape by connecting at R1.]
(;W[qs]
;B[pr])
(;W[pr]
;B[qs])))
