(;GM[1]FF[4]AP[Drago:4.22.03]SZ[19]CA[UTF-8]AB[rr][qq][pq][oq][nq][nr][ns][pr]AW[ms][mr][mq][mp][np][op][pp][qp][rp][rq][sr][os][ps]C[Black to play and live]
(;B[rs]C[This doesn't make the space big enough];W[qs]C[Black dies.])
(;B[qs]C[This is the best Black can do]
(;W[ss]C[If White tries to kill...];B[sq]C[... this is the trick to make it alive.];W[sp];B[or];W[sq];B[rs])
(;W[rs]C[White has to play this way.]
(;B[ss];W[sq];B[or]
;W[rs]C[This is a Ko and Black has to find the first threat.])
(;B[or]
;W[qr]C[This is also a Ko, but Black has to win it twice.]))))
