(;GM[1]FF[4]CA[UTF-8]AP[CGoban:3]ST[2]RU[Japanese]SZ[9]KM[0.50]GN[Endgame - black to play and win]PB[You]AW[eb][fb][gb][ib][dc][hc][ad][bd][gd][hd][id][be][af][cf][ef][gf][hf][bg][eg][gg][bh][gh][hh]AB[cb][db][ac][bc][cc][cd][dd][fd][de][ee][ge][he][ie][df][ff][dg][fg][ch][dh][fh][fi](;B[ih];W[ig];B[gi];W[hi];B[bi];W[ec];B[ea];W[fa];B[da];W[fc];B[ah];W[if];B[fe];W[ag];B[ci];W[ai];B[cg];W[ce];B[ah];W[ed];B[ai]C[Incorrect. Black has 12 points and white has 12 points. White wins by half a point.])(;B[ig];W[if];B[fe];W[ih];B[gi];W[hi];B[bi];W[ec];B[ea];W[fa];B[da];W[fc];B[ah];W[ag];B[ci];W[ai];B[cg];W[ce];B[ah];W[ed];B[ai]C[Incorrect. Black has 12 points and white has 12 points. White wins by half a point.])(;B[bi];W[ec];B[ea];W[fa];B[da];W[fc];B[gi];W[hi];B[ah];W[if];B[fe];W[ag];B[ci];W[ai];B[cg];W[ce];B[ah];W[ed];B[ai]C[Incorrect. Black has 12 points and white has 12 points. White wins by half a point.])(;B[ec];W[ci];B[di];W[bi];B[ea];W[fa];B[da];W[fc];B[gi];W[if];B[fe];W[hi];B[cg];W[ce]C[Incorrect. Black has 14 points and white has 15 points. White wins by 1,5 points.])(;B[fe](;W[ig];B[gi];W[hi];B[bi];W[ec];B[ea];W[fa];B[da];W[fc];B[ah];W[ag];B[ci];W[ai];B[cg];W[ce];B[ah];W[ed];B[ai];W[if]C[Correct! Black has 12 points and white has 11 points. Black wins by half a point.])(;W[gi]C[This is not good, as this will leave a seki in the corner.];B[ig];W[if];B[ih](;W[ii]C[White cannot start this ko.];B[hi]C[White has no threats.])(;W[ci]C[Playing elsewhere is also no good.];B[di];W[bi](;B[hi]C[Playing here would be a mistake for black, as black also has no ko threats.];W[ii];B[ec];W[hg];B[ea];W[fa];B[da];W[fc];B[cg];W[ce])(;B[ec];W[da];B[ca];W[ea];B[fc];W[cg];B[ce];W[gc];B[ii]C[Black can make a seki in the corner, as white can never start the ko. White has 11 points and black has 12 points. So black wins by half a point again.])))(;W[if]C[This move leaves the same problem of ko / seki in the corner.];B[ih](;W[ig]C[White cannot play here.];B[hi]C[White is dead.])(;W[gi]C[When white plays here, it will revert to the same shape as before.];B[ig]C[White cannot start the ko and black creates a seki.];W[ci];B[di];W[bi];B[ec];W[da];B[ca];W[ea];B[fc];W[cg];B[ce];W[gc];B[ii]C[White has 11 points and black has 12 points. So black wins by half a point again.]))(;W[ci]C[Playing tenuki altogether is also not possible, the lower right corner will die.];B[ig];W[if];B[gi];W[hi];B[ih]C[Black wins, white's corner is dead.])))