(;GM[1]FF[4]AP[Drago:4.22.03]SZ[19]CA[UTF-8]AB[rr][rq][rp][qp][po][oo][no][mp][mq][nq][kp][kq][kr]AW[lr][mr][nr][oq][op][np][qq][qr][pr]C[Black to play and kill.]
(;B[pp]C[This takes away one potential eye.];W[os];B[pq]
;W[qs]C[But White can make two eyes still.])
(;B[qs];W[pp];B[os]
;W[ps]C[White lives easily.])
(;B[os]C[This is correct first play.];W[ns]
;B[or]C[Black sacrifices a second stone.];W[ps];B[or];W[os]
;B[pp]C[Now it takes two plays to make two eyes, so White is dead.]
(;W[pq];B[ls])
(;W[ls];B[pq])))
