(;GM[1]FF[4]CA[UTF-8]AP[CGoban:3]ST[2]
RU[Japanese]SZ[19]KM[0.00]
PB[Black to play and live]AW[nm][on][pn][qn][no][ro][np][rp][nq][oq][rq][nr]AB[oo][po][qo][op][qp][pq][qq][or]
(;B[ps]C[Sometimes this is the move to make eye shape.]
;W[qr]C[However, even with the corner nearby, Black cannot trap this stone.]
;B[rr]
;W[rs]
;B[sr]
;W[sq])
(;B[rr]C[So this must be the first move.]
(;W[pr]
;B[qr]
;W[os]
;B[sr]C[This way is easy live for Black.])
(;W[sr]C[This is White's strongest attack.]
(;B[qs]C[Black should not play here next.]
;W[rs]C[White can start a Ko with this move.])
(;B[ps]C[Black should now play here. ]
;W[qr]
;B[rs]C[Now the corner comes to Black's rescue and there
are two eyes.]))
(;W[os]
;B[sr]C[Black must play here if White attacks from the other side.]
;W[qs]
;B[pr]
;W[ps]
;B[rs]C[Still two eyes.])))
