(;AB[ba]AB[bb]AB[bc]AB[ab]AB[cc]AB[cd]SZ[12]AB[ad]AB[ae]AB[be]AB[dc]AB[ec]AB[fc]AW[cb]AW[da]AW[ea]AW[fa]AW[fb]AB[eb]AW[gc]AW[hc]AW[gd]AW[fd]AW[ed]AW[dd]AW[de]AW[ce]AW[af]AW[bf]AW[ag]AW[bg]AW[cf]AW[cg]AW[bh]AW[df]AW[ef]AW[fe]AB[ah]AB[ai]AB[bi]AB[ch]AB[ci]AB[cj]AB[dg]AB[eg]AB[fg]AB[ff]AB[gf]AB[hd]AB[he]AB[ic]AB[jc]AB[kc]AW[ib]AW[ia]AW[ha]AB[jb]AB[ja]AW[kb]AB[db]C[Black plays the marked stone, how White should respond?]TR[db]AW[ak]AW[bk]AW[ck]AW[fk]AW[ek]AW[gk]AW[dk]AW[hk]AW[ik]AB[jk]AB[jj]AB[kj]AB[ki]AB[li]AB[jl]AB[ii]AB[jh]AB[ji]AW[kd]AW[ke]AW[kf]AW[jf]AW[jg]AW[kh]AW[lh]AW[lf]AW[ld]AW[if]AW[ig]AW[hg]AW[hh]AB[hi]AW[gj]AW[gi]AB[fi]AB[eh]AB[ei]AB[di]AB[gh]AB[gg]AB[lk]AB[il]AW[hl]AW[el]AW[bl]AB[hf]AB[jd]AP[goproblems] (;W[gb]C[Yes, this solves threads but white can gain more therritory if it, plays first at M10RIGHT];B[ca]C[Yes, this solves threads but white can gain more therritory if it, plays first at M10RIGHT]) (;W[ca];B[gb]) (;W[lc]C[Verry Good! Advanced players told me about this point on the comments. W gains more theritory and now continue with the problem...];B[ka]C[Verry Good! Advanced players told me about this point on the comments. W gains more theritory and now continue with the problem...];W[lb];B[gb] (;W[ga]C[RIGHT]) (;W[hb]C[RIGHT])))