(;GM[1]FF[4]SZ[19]CA[utf-8]AP[SmartGo One:1.6]GN[204dxRH]AB[np][op][qp][rp][sp][lq][lr][ls][mq][pq][pr][qq]AW[nq][oq][rq][rr][mr][ms][or][os][qr][ps]PM[2]C[Black to play and kill in ko.]FG[259:]
(;B[nr]C[Black must attack this eye first to reduce White's liberties. They cannot live in the corner if they give up this eye.];W[ns]
(;B[rs]C[Now if Black plays here]
(;W[sq]C[So White plays here];B[sr]C[Black plays here and White has to start the Ko as connecting fails in damezumari.]
(;W[ss]C[White has to win this ko to live.])
(;W[qs];B[nr]))
(;W[qs]C[If White plays here it just dies.];B[sr])
(;FG[259:]PM[2];W[sr]C[This dies also.];B[qs]))
(;B[sr]C[This also works, but is harder for White to get wrong.];W[sq];B[rs]
(;W[ss])
(;W[qs];B[nr])))
(;B[sr]C[This looks like the move to set up a ko.];W[sq];B[rs]
;W[qs]C[White has enough liberties to play here.];B[nr]
(;W[ss]
;B[ns]C[White just has to give up two stones whilst living in the corner.])
(;FG[259:]PM[2];W[ns]C[White here leaves all the stones in atari.];B[nr]))
(;B[rs]C[Likewise this doesn't kill the corner.]
(;W[sq]
(;B[sr];W[qs];B[nr];W[ss])
(;B[nr];W[ss];B[sr];W[qs];B[ns]))
(;W[qs];B[nr];W[sq])))
