Many players don't know, when to ignore a ko threat and when not, the key idea is : If Minimum profit from
a) ignoring opponents next threat
b) enemy ingoring your next threat
is bigger then profit from ighnoring this threat don't ignore threat.
Profit means value of winning the ko minus loss of ignoring ko threat when you win ko.
Play T for threat.
White has 0.5 points komi.
(;SZ[19]AW[fa]AW[ha]AW[ja]AW[ka]AW[oa]AW[pa]AW[qa]AW[sa]AW[eb]AW[fb]AW[hb]AW[kb]AW[pb]AW[qb]AW[sb]AW[bc]AW[cc]AW[dc]AW[ec]AW[fc]AW[kc]AW[mc]AW[sc]AW[fd]AW[kd]AW[ld]AW[md]AW[pd]AW[qd]AW[sd]AW[ee]AW[fe]AW[he]AW[ke]AW[pe]AW[qe]AW[se]AW[bf]AW[cf]AW[df]AW[ef]AW[ff]AW[hf]AW[kf]AW[sf]AW[eg]AW[fg]AW[kg]AW[lg]AW[mg]AW[pg]AW[qg]AW[sg]AW[eh]AW[fh]AW[kh]AW[lh]AW[ph]AW[qh]AW[sh]AW[bi]AW[ci]AW[di]AW[ei]AW[gi]AW[ki]AW[si]AW[ej]AW[kj]AW[lj]AW[mj]AW[nj]AW[pj]AW[qj]AW[sj]AW[ek]AW[gk]AW[lk]AW[qk]AW[sk]AW[bl]AW[cl]AW[dl]AW[el]AW[ll]AW[sl]AW[em]AW[fm]AW[gm]AW[lm]AW[pm]AW[qm]AW[sm]AW[dn]AW[fn]AW[gn]AW[kn]AW[ln]AW[qn]AW[sn]AW[bo]AW[co]AW[do]AW[eo]AW[go]AW[io]AW[jo]AW[lo]AW[so]AW[fp]AW[gp]AW[ip]AW[kp]AW[lp]AW[pp]AW[qp]AW[rp]AW[sp]AW[hq]AW[iq]AW[jq]AW[lq]AW[oq]AW[pq]AW[qq]AW[rq]AW[sq]AW[hr]AW[lr]AW[nr]AW[or]AW[qr]AW[sr]AW[hs]AW[os]AW[ps]AW[qs]AW[rs]AW[ss]AB[aa]AB[ca]AB[da]AB[ea]AB[ia]AB[la]AB[na]AB[ab]AB[cb]AB[db]AB[ib]AB[lb]AB[nb]AB[ob]AB[ac]AB[gc]AB[ic]AB[nc]AB[oc]AB[pc]AB[qc]AB[rc]AB[ad]AB[cd]AB[dd]AB[gd]AB[hd]AB[id]AB[nd]AB[ae]AB[ce]AB[de]AB[ie]AB[le]AB[ne]AB[oe]AB[af]AB[if]AB[lf]AB[nf]AB[of]AB[pf]AB[qf]AB[rf]AB[ag]AB[cg]AB[dg]AB[gg]AB[hg]AB[ig]AB[ng]AB[og]AB[ah]AB[ch]AB[dh]AB[hh]AB[ih]AB[nh]AB[oh]AB[ai]AB[ii]AB[mi]AB[oi]AB[pi]AB[qi]AB[ri]AB[aj]AB[cj]AB[dj]AB[fj]AB[gj]AB[hj]AB[ij]AB[oj]AB[ak]AB[ck]AB[dk]AB[hk]AB[jk]AB[mk]AB[ok]AB[al]AB[hl]AB[il]AB[jl]AB[ol]AB[pl]AB[ql]AB[rl]AB[am]AB[cm]AB[dm]AB[hm]AB[jm]AB[mm]AB[nm]AB[om]AB[an]AB[cn]AB[hn]AB[in]AB[jn]AB[mn]AB[on]AB[pn]AB[ao]AB[ho]AB[mo]AB[no]AB[po]AB[qo]AB[ro]AB[ap]AB[bp]AB[cp]AB[dp]AB[ep]AB[hp]AB[mp]AB[np]AB[op]AB[dq]AB[eq]AB[fq]AB[gq]AB[mq]AB[nq]AB[dr]AB[er]AB[fr]AB[gr]AB[ir]AB[jr]AB[kr]AB[mr]AB[es]AB[fs]AB[gs]AB[js]AB[ls]AB[ns]TR[ir]TR[jr]TR[kr]TR[js]TR[ls]TR[ns]C[White to make this one sided ko profitable enough to win.]GM[1]FF[4]CA[UTF-8]AP[CGoban:2]ST[2]RU[Japanese]KM[0.50]PW[white]PB[black]PL[B]
(;W[ms];B[rb]
(;W[ns];B[ra]C[black won by 3,5 moku]TW[en]TW[fo]TW[ko]TW[jp]TW[kq]TW[ir]TW[jr]TW[kr]TW[pr]TW[rr]TW[is]TW[js]TW[ks]TW[ls]TB[oa]TB[pa]TB[qa]TB[pb]TB[qb]TB[ik]TB[im]TB[nn]TB[oo]TB[aq]TB[bq]TB[cq]TB[ar]TB[br]TB[cr]TB[as]TB[bs]TB[cs]TB[ds]PL[B])
(;W[ra];B[ns]LB[bb:T]C[Play threat at T.FORCE];W[bb];B[ba];W[ms];B[re]
(;W[ns];B[rd]C[black won by 2,5 moku]TW[en]TW[fo]TW[ko]TW[jp]TW[kq]TW[ir]TW[jr]TW[kr]TW[pr]TW[rr]TW[is]TW[js]TW[ks]TW[ls]TB[od]TB[pd]TB[qd]TB[pe]TB[qe]TB[ik]TB[im]TB[nn]TB[oo]TB[aq]TB[bq]TB[cq]TB[ar]TB[br]TB[cr]TB[as]TB[bs]TB[cs]TB[ds])
(;W[rd];B[ns]LB[be:T]C[Play threat at T.FORCE];W[be];B[bd];W[ms];B[rh]
(;W[ns];B[rg]C[black won by 1,5 moku]TW[en]TW[fo]TW[ko]TW[jp]TW[pr]TW[rr]TB[pg]TB[qg]TB[ph]TB[qh]TB[ik]TB[im]TB[nn]TB[oo]TB[aq]TB[bq]TB[cq]TB[ar]TB[br]TB[cr]TB[as]TB[bs]TB[cs]TB[ds])
(;W[rg];B[ns]LB[bh:T]C[Play threat at T.FORCE];W[bh];B[bg];W[ms];B[rk]
(;W[ns];B[rj]C[black won by half moku]TW[en]TW[fo]TW[ko]TW[jp]TW[kq]TW[ir]TW[jr]TW[kr]TW[pr]TW[rr]TW[is]TW[js]TW[ks]TW[ls]TB[pj]TB[qj]TB[ik]TB[pk]TB[qk]TB[im]TB[nn]TB[oo]TB[aq]TB[bq]TB[cq]TB[ar]TB[br]TB[cr]TB[as]TB[bs]TB[cs]TB[ds])
(;W[rj];B[ns]LB[bk:T]C[Play threat at T.FORCE];W[bk]
(;B[bj];W[ms];B[rn]
(;W[ns];B[rm]C[RIGHT]TW[en]TW[fo]TW[ko]TW[jp]TW[kq]TW[ir]TW[jr]TW[kr]TW[pr]TW[rr]TW[is]TW[js]TW[ks]TW[ls]TB[ik]TB[im]TB[pm]TB[qm]TB[nn]TB[qn]TB[oo]TB[aq]TB[bq]TB[cq]TB[dq]TB[ar]TB[br]TB[cr]TB[dr]TB[er]TB[fr]TB[as]TB[bs]TB[cs]TB[ds]TB[es]TB[fs])
(;W[rm];B[ns];W[bn];B[ms];W[bm]C[black won by half moku]TW[cm]TW[dm]TW[cn]TW[en]TW[fo]TW[ko]TW[jp]TW[pr]TW[rr]TB[ik]TB[im]TB[nn]TB[oo]TB[aq]TB[bq]TB[cq]TB[dq]TB[ar]TB[br]TB[cr]TB[dr]TB[er]TB[as]TB[bs]TB[cs]TB[ds]TB[es]TB[fs]))
(;B[ms];W[bj]C[White won by by hlaf komi anyway]TW[cj]TW[dj]TW[ck]TW[dk]TW[en]TW[fo]TW[ko]TW[jp]TW[pr]TW[rr]TB[ik]TB[im]TB[nn]TB[oo]TB[aq]TB[bq]TB[cq]TB[ar]TB[br]TB[cr]TB[as]TB[bs]TB[cs]TB[ds]))))))
(;W[is];B[ms]C[White have lost by 7,5 moku]))
