(;AB[bd]AB[cd]AB[dc]AB[ec]AB[fc]AB[fe]AB[ff]AB[ef]AB[jd]AB[jf]AB[jh]AB[ih]AB[gh]AB[gi]AB[fj]AB[ej]AB[dj]AB[di]AB[ci]AB[bf]AW[dd]AW[ed]AW[ee]AW[df]AW[ce]AW[be]AW[ae]AW[af]AW[cg]AW[ch]AW[eg]AW[eh]AW[fi]AW[fg]AW[gg]AW[gj]AW[hj]AB[ag]AW[ld]AW[lf]AW[lh]AW[em]AB[cm]C[Black to kill.]AP[goproblems] (;B[bg] (;W[ah] (;B[bi];W[bh];B[dh]C[RIGHT]) (;B[bh];W[bi];B[ai];W[bj]) (;B[dh] (;W[bi];B[bj]C[Correct. White can get neither seki nor life from this.RIGHT]) (;W[aj];B[bi];W[bh];B[ai]C[RIGHT]))) (;W[bh] (;B[bi] (;W[ah];B[dh]C[RIGHT]) (;W[dh];B[ah])) (;B[dh];W[bi];B[bj];W[ai] (;B[dg]C[This is not seki because the B15 group is not attached to the B12 group, and so C14 is not white territory..RIGHT]) (;B[aj];W[dg]C[Seki. Black can do better.])) (;B[ah];W[bi]))) (;B[bh];W[bg] (;B[dh];W[bi]) (;B[bi];W[dh]) (;B[ah];W[bi]) (;B[ai];W[dh])) (;B[ah];W[bg] (;B[dh];W[bi]C[If white would have made the mistake of playing B11 at A11, black could kill. But B11 is the responce here that gives life.]) (;B[bi];W[dh])) (;B[bi] (;W[bg] (;B[dh];W[bh] (;B[ah];W[ai] (;B[ah]C[Correct.RIGHT]) (;B[aj];W[ah])) (;B[ai];W[ah])) (;B[ah];W[dh])) (;W[dh];B[bg];W[bh];B[ah])) (;B[ai];W[bg];B[dh];W[ah]) (;B[dh];W[bi] (;B[bj];W[bg] (;B[ai];W[ah];B[bh]C[Ko. Black can do better.]) (;B[ah];W[ai]C[White lives.])) (;B[bg];W[bj]C[White can live easily.]) (;B[dg];W[bj]C[White lives nicely along the bottom. Your capture of five stones is a poor result as black could have killed the whole group.]) (;B[bh] (;W[bj]C[White can extend along the second line or play B13 if she needs to.]) (;W[bg]C[White lives with an eye at B14 and another around A12.]))) (;B[fd];W[dh] (;B[bg];W[bh];B[ah];W[bi]C[White lives. The potential loss of the three stones is nothing.]) (;B[bh];W[bg]) (;B[ah];W[bg];B[bi]) (;B[de];W[bg]C[White lives. You got the six points from capturing, but you could have killed it all.])))