(;AW[ab]AW[bb]AW[cc]AW[cd]AW[dd]AW[ed]AW[fb]AW[ec]AB[gb]AB[gc]AB[fc]AB[fd]AB[fe]AB[ee]AB[de]AB[ce]AB[be]AB[bd]AB[bc]LB[bg:kill]LB[dg:ko]LB[fg:seki]LB[hg:tenuki]C[Black to play, what is the best he can do? If you think there is only endgame, play at tenuki]AP[goproblems]
(;B[bg];W[bh]
(;B[db];W[eb]
(;B[cb]
(;W[ba];B[da]C[RIGHT])
(;W[ca];B[ba]C[RIGHT])
(;W[da]C[CHOICE]
(;B[ca]
(;W[fa]
(;B[ba];W[dc]
(;B[ac];W[aa];B[cb]C[RIGHT])
(;B[ea]C[This only gives White an extra ko threat here, you should go straight for the kill. This is not a real ko.]))
(;B[ea]C[This only gives White an extra ko threat here, you should go straight for the kill. This is not a real ko.])
(;B[ac];W[dc]
(;B[ba];W[aa];B[cb]C[RIGHT])
(;B[ea]C[This only gives White an extra ko threat here, you should go straight for the kill. This is not a real ko.]))
(;B[ga];W[ba]C[Black can kill without ko]))
(;W[ba];B[ea];W[fa];B[ac]C[RIGHT]))
(;B[ba];W[dc]C[white lives])
(;B[ea];W[fa]
(;B[ga];W[ca]C[White lives])
(;B[ca];W[ba]C[Black can kill without ko.])
(;B[ac];W[ca]C[White lives])
(;B[ba];W[dc]C[White lives]))))
(;B[fa];W[ca]C[White lives]))
(;B[eb];W[db]C[white is alive])
(;B[ea];W[db]C[white is alive])
(;B[ca];W[db]C[white is alive])
(;B[cb];W[db]C[white is alive])
(;B[ba];W[db]C[white is alive])
(;B[da];W[db]
(;B[ea];W[ca]C[white is alive])
(;B[ca];W[ea]C[white is alive]))
(;B[fa];W[db]C[white is alive]))
(;B[dg];W[dh]
(;B[db];W[eb]
(;B[cb];W[da]
(;B[ca];W[fa]
(;B[ga];W[ba];B[ea]C[It's a ko, but Black can kill without ko])
(;B[ba];W[dc];B[ea]C[It's not a real ko, but Black can kill without ko])
(;B[ea];W[he]TR[hd]C[Respond to the threat]
(;B[hd];W[da]
(;B[ga];W[ba];B[ea]C[It's a ko, but Black can kill without ko])
(;B[ba];W[dc]TR[ac]
(;B[ac]C[It wasn't a ko after all.])
(;B[ea]C[NOTTHIS])
(;B[ga]C[NOTTHIS]))
(;B[ac];W[dc]
(;B[ba]C[It wasn't a ko after all.])
(;B[ea]C[NOTTHIS])))
(;B[gd]C[NOTTHIS])
(;B[hc]C[NOTTHIS])
(;B[ic]C[NOTTHIS])
(;B[id]C[NOTTHIS])
(;B[ie]C[NOTTHIS])
(;B[ge]C[NOTTHIS])
(;B[ba]C[NOTTHIS])
(;B[ac]C[NOTTHIS])
(;B[ga]C[NOTTHIS]))
(;B[ac];W[dc]TR[ba];B[ba];W[aa]TR[cb];B[cb]C[It wasn't a ko after all.]))
(;B[ba];W[dc]C[white lives]))
(;B[ea];W[ca]C[White lives]))
(;B[eb];W[db]C[white is alive])
(;B[ca];W[db]
(;B[cb];W[da]C[white is alive])
(;B[fa];W[eb]C[white is alive])
(;B[da];W[ea]C[white is alive]))
(;B[cb];W[db]C[white is alive])
(;B[da];W[db]C[white is alive])
(;B[ea];W[db]C[white is alive])
(;B[fa];W[db]C[white is alive])
(;B[ba];W[db]C[white is alive]))
(;B[fg];W[fh]
(;B[db];W[eb];B[cb];W[da]
(;B[ca];W[fa]TR[ba]
(;B[ba];W[dc]TR[ac]
(;B[ac];W[aa]TR[cb];B[cb]C[white is dead])
(;B[ea]C[NOTTHIS])
(;B[ga]C[NOTTHIS]))
(;B[ga]C[NOTTHIS])
(;B[ea]C[NOTTHIS]))
(;B[ba];W[dc]C[white lives]))
(;B[eb];W[db]C[white is alive])
(;B[cb];W[db]C[white is alive])
(;B[ca];W[db]C[white is alive])
(;B[da];W[db]C[white is alive])
(;B[ea];W[db]C[white is alive])
(;B[ba];W[db]C[white is alive]))
(;B[hg];W[db]C[white is alive now])
(;B[af]C[NOTTHIS])
(;B[bf]C[NOTTHIS])
(;B[cf]C[NOTTHIS])
(;B[df]C[NOTTHIS])
(;B[ef]C[NOTTHIS])
(;B[ff]C[NOTTHIS])
(;B[gf]C[NOTTHIS])
(;B[hf]C[NOTTHIS])
(;B[if]C[NOTTHIS])
(;B[ig]C[NOTTHIS])
(;B[ih]C[NOTTHIS])
(;B[hh]C[NOTTHIS])
(;B[gh]C[NOTTHIS])
(;B[fh]C[NOTTHIS])
(;B[eh]C[NOTTHIS])
(;B[dh]C[NOTTHIS])
(;B[ch]C[NOTTHIS])
(;B[bh]C[NOTTHIS])
(;B[ah]C[NOTTHIS])
(;B[ag]C[NOTTHIS])
(;B[cg]C[NOTTHIS])
(;B[eg]C[NOTTHIS])
(;B[gg]C[NOTTHIS])
(;B[eb]C[NOTTHIS])
(;B[db]C[NOTTHIS])
(;B[dc]C[NOTTHIS])
(;B[cb]C[NOTTHIS])
(;B[ca]C[NOTTHIS])
(;B[da]C[NOTTHIS])
(;B[ea]C[NOTTHIS])
(;B[fa]C[NOTTHIS])
(;B[ba]C[NOTTHIS])
(;B[ga]C[NOTTHIS]))