(;AB[aq]AB[ar]AB[bq]AB[cq]AB[dq]AB[dr]AB[er]AW[br]AW[cr]AW[cs]AW[bp]AW[cp]AW[dp]AW[eq]AW[fq]AW[fr]AW[fs]AW[bn]C[Save black's stones!]AP[goproblems] (;B[bs];W[as] (;B[ds]C[Correct! If there had been white stones at A and B, this process would not work, but because you have liberties, white cannot connect to make a bulky-five killing shape.RIGHT]LB[ap:A]LB[es:B]) (;B[es];W[bs]C[Bulky-five is dead. Capture to see why.];B[ds];W[bs]LB[bs:A]C[Stone 'A' is the vital point to kill a bulky-five.]) (;B[ap];W[bs]C[Bulky-five is dead. Capture at A to see why.]LB[ds:A];B[ds];W[bs]LB[bs:A]C[A is the vital point to kill bulky-five.])) (;B[as];W[bs]C[A 2x2 square is dead. Capture to see why.];B[ds];W[cr]C[Black has no way of making two eyes.]) (;B[ds];W[bs]C[A 2x2 square is a killing shape. Capture to see why.];B[as];W[cr]C[Black has no way of making two eyes.]) (;B[es];W[bs]C[A 2x2 square is a killing shape. For the purposes of teaching, please play at A.]LB[ds:A];B[ds];W[ap]LB[as:A];B[as];W[cr]C[Black has no way of making two eyes, therefore, 2x2 square is dead.]) (;B[ap];W[bs]C[Pushing does not accomplish anything.]))