(;AB[ds]AB[dr]AB[dq]AB[ep]AB[fp]AB[gp]AB[gq]AB[hp]AB[iq]AB[jr]AB[kr]AB[jp]AB[is]AW[js]AW[ir]AW[hr]AW[hq]AW[gr]AW[fq]AW[eq]AW[er]AW[es]AW[fs]AP[goproblems] (;B[hs]C[];W[gs] (;B[is]C[By sacrificing the first black stone you play at H1, and the stone that is already at J1, you can then play at J1. By doing so you kill the white stones, because if white takes your stone then it has a false eye, and if he doesn't then he doesn't have an eye.RIGHT]) (;B[ks];W[is]C[W has two eyes now and is therefore alive!])) (;B[gs]C[];W[hs]C[W has two eyes now and is therefore alive!]) (;B[ks];W[hs]C[W has two eyes now and is therefore alive!]))