(;AB[pa]AB[pb]AB[oa]AB[nb]AB[mb]AB[ma]AB[mc]AB[lb]AB[kb]AB[jb]AB[ja]AB[ib]AW[ha]AW[hb]AW[hc]AW[ic]AW[jc]AW[kc]AW[lc]AW[md]AW[nc]AW[oc]AW[ob]AW[pc]AW[od]AW[oe]AW[pe]AW[ne]AB[pd]AB[qd]AB[qc]AB[rc]AB[qe]AB[of]AB[pf]AB[pg]AB[qg]AB[rg]AB[rf]AB[sf]AW[sg]AW[sh]AW[rh]AW[qh]AW[ph]AW[oh]AW[og]AW[nf]AW[qb]AW[rb]LB[nf:1]LB[jf:T]C[White just played 1. Defend only if you need to. Play tenuki at 'T' if you can! (Avoid ko!)]AP[goproblems] (;B[jf] (;W[sc] (;B[qa] (;W[sd] (;B[ra] (;W[sb] (;B[rd];W[se];B[na]C[Great! You keep all your points.RIGHT]) (;B[se];W[rd];B[na]C[Great! You keep all your points.RIGHT]) (;B[re];W[ia];B[na];W[ka]C[seki]) (;B[na];W[re]LB[rd:A]LB[se:B]C[Black can play neither A nor B and dies.])) (;W[re];B[sb])) (;B[rd];W[se] (;B[ra];W[sb];B[na]C[Great! You keep all your points.RIGHT]) (;B[sb];W[sa];B[na]C[Great! You keep all your points.RIGHT])) (;B[se];W[rd] (;B[ra];W[sb];B[na]C[Great! You keep all your points.RIGHT]) (;B[sb];W[sa];B[na]C[Great! You keep all your points.RIGHT])) (;B[sb];W[sa] (;B[rd];W[se];B[na]C[RIGHT]) (;B[se];W[rd];B[na]C[Great! You keep all your points.RIGHT]) (;B[re];W[ia];B[na];W[la]C[Seki.]) (;B[na];W[re];B[ra];W[sb]LB[rd:A]LB[se:B]C[Black can play neither A nor B, and is dead.])) (;B[re];W[ra] (;B[na];W[sb]) (;B[sb];W[na])) (;B[sa];W[sb];B[na];W[re])) (;W[ra];B[na] (;W[sb];B[sd]C[White gave away an extra point this way.CHOICERIGHT]) (;W[sd];B[sb] (;W[sa];B[sb]C[RIGHT]) (;W[re];B[sa];W[rb];B[ra]C[RIGHT]))) (;W[re];B[sd]C[RIGHT])) (;B[sa];W[sd] (;B[rd];W[se];B[sb];W[ra];B[sb];W[sa];B[na]C[Black wins again.RIGHT]) (;B[se];W[rd];B[sb];W[ra];B[sb];W[sa];B[na]C[Black wins again.RIGHT]) (;B[re];W[sb]) (;B[sb];W[re] (;B[na];W[ra];B[sb];W[sa];B[qa];W[sb]LB[rd:A]LB[se:B]C[Black can play neither A nor B and is dead.]) (;B[qa];W[ra] (;B[na];W[sb]) (;B[sb];W[na]))) (;B[qa];W[sb];B[na];W[ra])) (;B[ra];W[sa] (;B[qa];W[na]) (;B[na];W[qa];B[sd];W[ia]C[This ko could have been avoided.]) (;B[sd];W[qa];B[na];W[ia]) (;B[sb]C[This is two-step ko, so quite good, but black can avoid ko completely.])) (;B[sd];W[qa];B[na];W[sa]C[This is a two-step ko, so quite good, but still unnecessary.]) (;B[sb];W[sa] (;B[qa];W[sd] (;B[rd];W[se];B[na]C[RIGHT]) (;B[se];W[rd]) (;B[re];W[ia];B[na];W[la]C[Seki.]) (;B[na];W[re];B[ra];W[sb]LB[rd:A]LB[se:B]C[Black can play neither A nor B, and is dead.])) (;B[sd];W[qa];B[na];W[ia])) (;B[na] (;W[qa] (;B[sa]C[Great! You keep all your points.RIGHT]) (;B[sd];W[sa])) (;W[sd] (;B[rd];W[se] (;B[sb];W[sa];B[qa]C[RIGHT]) (;B[qa];W[sb];B[ra]C[CHOICERIGHT]) (;B[sa];W[sb] (;B[qa];W[ra]) (;B[ra];W[qa])) (;B[ra];W[sb];B[qa]C[RIGHT])) (;B[se];W[rd] (;B[sb];W[sa];B[qa]C[RIGHT]) (;B[qa];W[sb];B[ra]C[RIGHT]) (;B[ra];W[sb];B[qa]C[RIGHT]) (;B[sa];W[sb] (;B[qa];W[ra]) (;B[ra];W[qa]))) (;B[sb];W[re] (;B[qa];W[sa];B[ra];W[sb]C[Black dies.]) (;B[ra];W[sa]C[This ko could have been avoided.])) (;B[qa];W[re];B[ra];W[sb]) (;B[ra];W[re];B[sb];W[sa]C[This ko could have been avoided.])))) (;W[qa];B[na] (;W[ia];B[sb]) (;W[sa];B[sc]) (;W[sc] (;B[sa]C[Great! You keep all your points.RIGHT]) (;B[sd];W[sa])))) (;B[sb];W[jf]C[This is the right move for defending, but will not be needed until white has played J19.]) (;B[qa];W[jf]C[T18 is better, since with this move, you will have to add another stone when white plays J19.]) (;B[ra];W[jf]C[You do not have to defend until white plays J19.]) (;B[sa];W[jf]C[You need not defend until white plays J19.]) (;B[sc];W[jf]C[T18 would be a better way to defend, since with this move, you will have to add one more stone after white J19.]) (;B[sd];W[jf]C[You do not have to defend until white plays J19, and T18 would suffice then.]) (;B[se];W[jf]C[You do not have to defend until white plays J19, and T18 would suffice then.]) (;B[na];W[jf]C[You do not have to defend until white plays J19.]))