Many go players dislike ko fights; understandably so, for they are
forced not only to think about the local situation, which is likely to be
complicated enough, but to weigh it against all the ko threats available
to both players, to weigh those ko threats against each other, and
preferably to do so before the ko begins. It follows, therefore, that if you
can start a ko fight that you have a fair chance of winning, you may
have scored a psychological, as well as a tactical, triumph. There are
many simple tesuji for causing ko. Consider the following:
(;AB[rr]AB[qr]AB[pr]AB[or]AB[nr]AB[qq]AW[rq]AW[qp]AW[qo]AW[mr]AW[mq]AW[nq]AW[oq]AW[pq]C[In this posion Black seems to be alive. To start with, he is threatening to capture a stone with A.]LB[rp:A]AP[goproblems]
(;W[sr];B[rp];W[sp]C[Choosing a time when he is backed up by an adequate number of ko threats, White can unleash the double-hane tesuji at 1. Against Black 2, White plays 3 and the ko is on. This could be a nasty surprise for Black.RIGHT]LB[sr:1]LB[rp:2]LB[sp:3])
(;W[rp];B[sr]C[And even if White connects, Black 2 makes a living shape.White, however, should be in no rush to play 1, an endgame move, but should leave the position as it stands. Black A is gote. If White loses the ko, then of course he takes a certain loss on the right edge, but that should be more than compensated for by his ko threat. If Black loses, his whole group is dead; that will be harder to compensate for. This kind of ko fight, where you risk little or nothing and your opponent risks a lot, is the most fun and the most profitable.CHOICE]LB[rp:1]LB[sr:2])
(;W[ns];B[sr];W[os];B[ps];W[ms];B[rs]C[CHOICE])
(;W[rs];B[sr]
(;W[ns];B[os];W[qs];B[rp];W[ro];B[sq];W[so];B[sp]C[CHOICE])
(;W[qs];B[ns];W[ps];B[rp];W[ro];B[sq];W[so];B[sp]C[CHOICE]))
(;W[ps];B[sr];W[qs];B[rs]C[CHOICE])
(;W[qs];B[sr];W[rs];B[ns];W[ps];B[rp];W[ro];B[sq];W[so];B[sp]C[CHOICE])
(;W[os];B[sr]
(;W[ns];B[ps];W[ms];B[rs]C[CHOICE])
(;W[ps];B[qs]C[CHOICE])))