(;AP[goproblems]AW[nc]AW[nd]AW[ne]AB[lb]AW[kb]AB[jb]AB[jc]AB[jd]AW[ja]AW[ib]AW[ic]AW[id]AW[hd]AW[gd]AB[ie]AB[jf]AB[he]AB[ge]AB[fd]AB[fc]AB[fb]AB[me]AB[le]AW[nf]AW[ng]AB[pb]AB[pc]AB[pd]AB[qe]AW[qg]AW[qj]AB[gb]AB[je]C[W try to connect stones](;W[mb](;B[la]C[B makes a mistake];W[lc];B[kc];W[ma]C[Unconditional connection due to B mistake (ko is best when B plays optimally)CHOICERIGHT])(;B[kc];W[la]C[Ko - best resultCHOICERIGHT]))(;W[lc];B[kc](;W[ka];B[la](;W[ia];B[mc])(;W[mb];B[ia])(;W[mc];B[ia]))(;W[la];B[mb](;W[mc];B[ma])(;W[nb];B[ma])(;W[ma];B[na])(;W[ka];B[ma])))(;W[kc];B[lc])(;W[la];B[mb]))