(;AB[nr]AB[nq]AB[np]AB[op]AB[pp]AB[qo]AB[ro]AB[po]AB[os]AB[pr]AB[qr]AW[or]AW[oq]AW[pq]AW[qq]AW[qp]AW[rp]AW[rr]AW[qs]C[Can black kill white or get a ko? 'T' for tenuki.]AB[mr]AB[rn]LB[mn:T]AP[goproblems] (;B[sp];W[ps];B[sr];W[sq];B[rq];W[ss]C[];B[rs];W[sq]C[Life in double ko :(]) (;B[mn]C[]AW[mr]AW[nr]AW[nq]AW[np]AB[oq]AB[or]AW[os]AB[pq]AB[qq]AW[pr]AW[qr]AW[op]AW[pp]AW[po]AW[qo]AW[ro]AW[rn]AB[rp]AB[qp]AB[qs]AB[rr];W[sp]C[How to defend ?] (;B[ps];W[sr] (;B[sq];W[rq]C[Do you need a ko threat ?]LB[on:Yes] (;B[ss];W[rs];B[sq]C[Life in double ko, nice !RIGHT]) (;B[on]C[In fact, no :) You do not need to fight this ko.])) (;B[ss];W[sq])) (;B[rq];W[sr] (;B[ss];W[rs];B[ps];W[sq];B[ss];W[so]) (;B[ps];W[sq]))))