(;GM[1]FF[4]AP[Drago:4.22.03]SZ[19]CA[UTF-8]AB[rr][rq][sq][rp][qp][oq][pp][or]AW[pq][pr][op][np][nq][po][qo][ro][so][sp]C[Black to play and live.]
(;B[qs]C[If Black tries to make eye space with this or similar...];W[os]C[...the White plays here and Black's follow up is not sente.];B[qr];W[ss])
(;B[os]C[Correct is to add a third sacrifice stone.];W[ps];B[qs];W[nr]
;B[ss]C[Now Black uses the forcing move to make time to make two eyes.];W[ns];B[qr]))
