(;GM[1]FF[4]AP[Drago:4.22.03]SZ[19]CA[UTF-8]AW[sq][sr][rr][ps][pr][pq][oq][mr]AB[op][pp][qp][rp][sp][rq][nq][mq][or][lr][kq]C[Black to play and kill.]
(;B[qq]C[If Black plays too simply, White makes two eyes.];W[qr]
(;B[nr];W[rs])
(;B[rs];W[nr]))
(;B[nr];W[qq]
;B[rs]C[This is not a snap-back shape.];W[qs])
(;B[qr]
;W[qq]C[This also fails.])
(;B[rs]C[This is the correct play, being on the vital point both for eye-destroying and snap-back threatening.];W[qq];B[os]
(;W[nr]
;B[qr]C[This is a snap back.])
(;W[qs]C[This is of course self-atari.])
(;W[qr]
;B[nr]C[White is dead.])))
