(;GM[1]FF[4]CA[UTF-8]AP[CGoban:3]ST[2]
RU[Japanese]SZ[19]KM[0.00]
PB[Black to play and kill]AW[qp][rp][pq][rq][pr][rr]AB[po][qo][ro][op][pp][sp][oq][or][os]
(;B[sr]C[In this case white does have to play inside at once.]
;W[sq]
(;B[qs]
(;W[ps]C[If white tries to stop the black stone escaping...]
;B[qr]C[... then he is short of liberties.]
;W[qq]
;B[rs])
(;W[qr]
(;B[ps]C[Black must not be in a hurry to escape though]
;W[rs])
(;B[rs]C[He must play here next and then he can escape...]
;W[ps]C[.... as white blocking is self-atari.])))
(;B[rs]C[This as the second move does not work.]
;W[qs]
;B[qr]
;W[ss]
;B[ps]
;W[qq])
(;B[ps]C[Nor does pushing next.]
;W[qs]
(;B[qr]
;W[qq]
;B[rs]
;W[ss])
(;B[rs]
;W[ss])))
(;B[sq]C[Reducing the eye space first does not work this time.]
(;W[sr]C[Though white must be careful after playing here.]
;B[qs]
(;W[ps]
;B[qr]
;W[qq]
;B[rs])
(;W[rs]
;B[qr])
(;W[qr]C[This is the move that makes 2 eyes.]
;B[ps]
;W[rs]))
(;W[qr]C[This just fails]
;B[sr]))
(;B[ps]
;W[qs]))
