Please report any mistake. Do not make any unnecessary moves.
Thanks to Bass.
Some moves are blocked in the beginning because they are Black's privilege and he can play them anytime (this allows me not to add dozens of variations).
(;SZ[13]AW[fb]AW[ec]AW[dc]AW[cb]AW[bb]AW[fd]AW[fe]AW[bg]AW[be]AW[bh]AW[ci]AW[cj]AW[dk]AW[ek]AW[dh]AW[eh]AW[eg]AW[ef]AW[df]AW[he]AW[ge]AW[ld]AW[le]AW[ke]AW[kf]AW[jf]AW[jg]AW[jh]AW[ji]AW[kj]AW[ll]AW[lk]AW[ki]AW[if]AW[gh]AW[gk]AW[hl]AW[il]AW[fl]AW[gm]C[Black to play. Black and White have 1 prisoner each. Komi is 6,5.]AB[lc]AB[kd]AB[jd]AB[ic]AB[ie]AB[hd]AB[gd]AB[gc]AB[fc]AB[ed]AB[dd]AB[cc]AB[bc]AB[bd]AB[de]AB[ce]AB[cf]AB[cg]AB[dg]AB[ch]AB[bf]AB[ab]AB[ad]AB[kg]AB[kl]AB[kk]AB[jj]AB[ik]AB[hk]AB[hi]AB[ii]AB[gj]AB[fi]AB[ej]AB[fh]AB[gg]AB[hg]AB[ig]AB[hf]AB[el]AB[li]AW[lj]CA[ISO8859-1]ST[2]FF[4]GM[1]AP[GOWrite:2.3.16]PM[2]KM[6,5]GN[ ]PB[ ]PW[ ]FG[259:]
(;B[md];W[me];B[mc];W[je]
(;B[id];W[ih];B[hh];W[jl];B[jk];W[km]
(;B[ag];W[ai];B[fj];W[dj];B[fk];W[gl]C[Black wins by 0,5.RIGHT])
(;B[fj];W[dj]
(;B[fk];W[gl];B[ag];W[ai]C[Black wins by 0,5.RIGHT])
(;B[ag];W[ai];B[fk];W[gl]C[Black wins by 0,5.RIGHT])))
(;B[lm];W[gb];B[hb];W[id];B[hc];W[kc]C[Black collapses.])
(;B[ff];W[ee];B[di];W[ei]C[Black lost one point for nothing (compare with correct solution) and still has to connect the ko.]))
(;B[mc];W[je]
(;B[id];W[ih];B[hh];W[jl];B[jk];W[km]
(;B[ag];W[ai]
(;B[fj];W[dj]
(;B[fk];W[gl])
(;B[md];W[me]))
(;B[md];W[me];B[fj];W[dj];B[fk];W[gl]C[Black wins by 0,5.RIGHT]))
(;B[fj];W[dj]
(;B[fk];W[gl];B[ag];W[ai];B[md];W[me]C[Black wins by 0,5.RIGHT])
(;B[ag];W[ai]
(;B[fk];W[gl];B[md];W[me]C[Black wins by 0,5.RIGHT])
(;B[md];W[me];B[fk];W[gl]C[Black wins by 0,5.RIGHT]))
(;B[md];W[me]
(;B[fk];W[gl];B[ag];W[ai]C[Black wins by 0,5.RIGHT])
(;B[ag];W[ai]))))
(;B[lm];W[gb];B[hb];W[id];B[hc];W[kc]))
(;B[lm];W[mc];B[lb];W[mb]C[And Black loses by half a point (too many variations to show them here). Please check for yourself.])
(;B[fj]C[Too early. This move is Black's privilege. Black should wait before playing it (for example, it can be a useful ko threat).NOTTHIS])
(;B[ag]C[Too early. This move is Black's privilege. Black should wait before playing it (for example, it can be a useful ko threat).NOTTHIS]))