(;AW[ga]AW[ab]AW[bb]AW[gb]AW[cc]AW[dc]AW[ec]AW[fc]AB[ba]AB[hb]AB[bc]AB[gc]AB[ic]AB[bd]AB[cd]AB[dd]AB[ed]AB[fd]AB[gd] (;B[cb];W[db] (;B[ea] (;W[ca] (;B[fb];W[eb];B[ha];W[aa]C[Black captures two stones in sente.RIGHT]) (;B[da];W[cb])) (;W[da];B[fb];W[ca]C[Black captures two stones in sente.RIGHT]) (;W[fb];B[da]C[ko for the whole group.])) (;B[da];W[ea] (;B[fb];W[ca]C[Black achieves nothing.]) (;B[ca];W[aa]) (;B[ac];W[ca])) (;B[ca];W[da] (;B[fb];W[fa]) (;B[ac];W[aa]C[Black achieves nothing.])) (;B[fb] (;W[ea] (;B[ha] (;W[ca];B[fa];W[eb]C[Black captures two stones in sente, but white is left with more points than in the correct solutions.]) (;W[fa];B[ca]C[Oops... White dies.])) (;B[ca];W[da] (;B[ha];W[aa] (;B[fa];W[ca]C[Black captures 2 stones in sente.RIGHT]) (;B[ca];W[fa])) (;B[ac];W[aa]))) (;W[ca] (;B[ea];W[eb];B[ha];W[aa]C[Black captures two stones in sente.RIGHT]) (;B[fa]C[This captures two stones, but in gote.]) (;B[ha]C[This captures two stones, but in gote.]))) (;B[ac];W[ca])) (;B[da];W[cb] (;B[ca];W[ea] (;B[fb];W[eb]C[White wins.]) (;B[eb];W[fb];B[fa];W[db]C[Black achieves nothing.])) (;B[fb];W[eb] (;B[ea];W[fa] (;B[ha];W[fb] (;B[ac];W[ca]) (;B[ca];W[aa])) (;B[ca];W[db])) (;B[ha];W[fa];B[ea];W[fb] (;B[ca];W[aa]) (;B[ac];W[ca]))) (;B[eb];W[fb];B[ca];W[ea];B[fa];W[db]) (;B[ea];W[fb];B[ca];W[db] (;B[ha];W[eb];B[ac]C[Black gets a seki this way, but it is gote.]) (;B[ac];W[eb];B[ha]C[Black gets a seki, but it is gote.])) (;B[ha];W[fb] (;B[ca];W[ea]) (;B[eb];W[ca]) (;B[ea];W[ca]))) (;B[fb] (;W[da] (;B[ea];W[eb] (;B[cb];W[fa];B[ac]C[Black captures two stones, but this is gote.]) (;B[ha];W[fa]C[Black achieves nothing.])) (;B[fa];W[eb] (;B[ha];W[cb]C[Black captures two stones in sente.Note that white C18 is necessary because of black C18-white C19-black E19.RIGHT]) (;B[cb];W[ca];B[ha];W[db]C[RIGHT]) (;B[ca];W[ea] (;B[cb];W[db]) (;B[ha];W[cb]))) (;B[eb];W[ea]C[Black achieves nothing. One piece of comfort: This is how I played when I got this position in a game.]) (;B[cb];W[ca] (;B[fa]C[Black captures two white stones, but in gote.]) (;B[ea];W[db]C[Black captures two stones in sente.RIGHT]) (;B[eb];W[db];B[ha]C[Black captures two stones this way, but in gote.])) (;B[ha];W[eb];B[fa];W[cb]C[Black captures two stones in sente. Note that whtie C18 is necessary because of black C18-white C19-black E19RIGHT]) (;B[ca];W[eb] (;B[cb];W[fa];B[ac]C[Black does capture two stones this way, but it is gote.]) (;B[ha];W[fa]C[Black achieves nothing.]) (;B[fa];W[ea];B[cb];W[db])) (;B[db];W[eb])) (;W[eb]C[White can play here, but it is not as good.];B[cb] (;W[da] (;B[fa];W[ca];B[ha];W[db]C[Now white has only four points (this move is necessary because black threatened E19 with double snap-back).]) (;B[ac]C[Black switches the scene.];W[fa]C[Now black gains the other two stone in sente. White's territory is only three points here.])) (;W[db];B[da]C[A ko is fought over the whole group.]))) (;B[ea];W[cb] (;B[fb];W[eb] (;B[ha];W[da];B[fa]C[Black captures two stones, but in gote.]) (;B[da];W[fa];B[ha];W[fb];B[ca];W[aa])) (;B[da];W[fb];B[ca];W[db];B[ha];W[eb];B[ac]C[Black makes a seki, but in gote.]) (;B[ca] (;W[fb]) (;W[da] (;B[db];W[eb] (;B[fb];W[fa]) (;B[ha];W[fb];B[ac]C[Black must win the ko to even get a gote seki; he can do much better.])) (;B[fb];W[eb] (;B[db];W[fa]) (;B[ha];W[fa])) (;B[ha];W[eb] (;B[db];W[fb];B[ac]C[Black must win a ko to even get a gote seki.]) (;B[fb];W[fa])))) (;B[ha];W[da] (;B[fb];W[eb];B[fa]C[Black captures two stones, but in gote]) (;B[eb];W[fb]) (;B[ca];W[aa] (;B[eb];W[fb]) (;B[fb];W[eb];B[fa]C[Black captures two stones, but in gote])))) (;B[db];W[cb]) (;B[ha];W[fb]C[Aji keshi.]) (;B[eb];W[fb] (;B[cb];W[db]) (;B[da];W[cb];B[ca];W[ea];B[fa];W[db]) (;B[ca];W[cb] (;B[da];W[ea];B[fa];W[db]) (;B[ea];W[da];B[db];W[fa]))) (;B[ca];W[cb] (;B[fb];W[eb] (;B[ha];W[fa]) (;B[ea];W[da] (;B[db];W[fa]) (;B[ha];W[fa])) (;B[da];W[ea])) (;B[da];W[fb] (;B[ea]C[Black can get a seki this way, but it will be in gote.];W[db] (;B[ha];W[eb];B[ac]C[Black gets a seki this way, but it is gote.]) (;B[ac];W[eb];B[ha]C[Black gets a seki, but it is gote.])) (;B[eb];W[ea];B[fa];W[db])) (;B[ea];W[fb]C[Black can get a seki this way, but it will be in gote (if black plays tenuki now, white can capture the black stones).]) (;B[eb];W[fb] (;B[da];W[ea];B[fa];W[db]) (;B[ea];W[da];B[db];W[fa]) (;B[db];W[ea])) (;B[ha];W[ea]C[Black achieves nothing.])) (;B[ac];W[cb] (;B[ha];W[fb]C[Much too small.]) (;B[fb];W[eb])))