(;GM[1]FF[4]CA[UTF-8]AP[CGoban:3]ST[2]
RU[Japanese]SZ[19]KM[0.00]
GN[175dx RMH]PB[Black to play and live]AW[ln][mn][nn][pn][lo][oo][lp][pp][qp][kq][rq][kr][lr][rr]AB[mo][no][mp][op][lq][mq][qq][mr][qr]
(;B[oq]C[It might look like blocking is too dangerous and that Black
should pull back here.]
;W[qs]
;B[pr]
;W[ms]C[White reduces the eye-space from both sides.]
(;B[ns]
(;W[os]C[White should not coninue here as Black can live.]BM[1]
(;B[ls]BM[1]
(;W[or]
;B[nr])
(;W[ps]
;B[or])
(;W[nr]
;B[ms]
;W[nq]
;B[or])
(;W[pq]
;B[or]))
(;B[ps]
;W[nr])
(;B[nr]
;W[ps]))
(;W[ps]C[White plays this way to kill Black.]BM[1]
;B[os]
;W[rs]BM[1]
;B[nq]
;W[or]))
(;B[os]
;W[nr]
;B[ns]
;W[nq]))
(;B[pq]C[So Black had better play here.]
(;W[oq]C[If White plays the atari, Black can give up one stone to live.]
;B[or]
;W[np]
(;B[nq]C[Black must not play here though.]
;W[op]
(;B[ns]
;W[qs])
(;B[ps]
;W[ms]))
(;B[ps]C[This is the correct way to live]
(;W[nr]
;B[ns])
(;W[ms]
;B[ns]
;W[nr]
;B[ls])
(;W[ns]
;B[ms]
;W[nr]
;B[os]
;W[ls]
;B[nq])))
(;W[or]C[However White can try playing in the eye space.]
;B[oq]
;W[nr]
;B[ns]
;W[nq]
;B[ps]C[This makes a seki shape and Black lives, but with no territory points.])))
