White is able to save the group in the top left corner if he chooses, how does he do it? This is a very long problem but you rarely need to read more than a couple moves ahead.
(;FF[4]GM[1]SZ[19]AP[SGFC:1.13b]
GN[temp2]
AW[ok][ab][bb][cb][da][ea][ma][be][cd][dd][fc][gb][ag][bg][cg][ac]
[ef][ed][fd][hd][gd][hf][je][jc][jd][jf][gh][bk][gm][hm][im]
[jj][ij][lh][ei][di][eg][ak][ai][ck][fm][mi][pl][qn][po][pm]
[pp][oq][lo][ko][kl][kk][io][bs][cr][cp][bq][co][db][ca][dr]
[fr][is][fq][al][il][gk][em][jr][kr][ir][ls][ms][rr][rs][or]
[sq][sp][sk][qi][kb][ri][rk][ph][la][md][ka][oa][of][na][pd]
[se][qe][qd][rb][sb][pf][mc][ld]AB[nl][bc][cc][dc][eb][fa][fb]
[ha][hc][ja][jb][ad][bd][ae][bf][cf][df][ee][fe][he][hg][gf]
[ii][kh][hi][dh][bj][cj][hl][fl][ik][hk][ol][pn][on][op][mo]
[kq][kj][jm][lj][in][jp][cq][ar][br][bp][ds][es][fs][dq][ap]
[as][ec][gs][ch][fp][eq][dp][am][an][fk][gl][cn][kp][hr]
[mr][nr][ns][ps][qr][rp][sn][sm][qk][ia][rl][pi][lc][ke][kc]
[mb][nb][qh][sg][rd][re][qf][rc][sc][oe][lb][kd]C[How can white save the group in the top left corner and capture some black stones?]
(;W[af];B[ga]C[Black should tenuki but he can't read that far.]
(;W[hb];B[ce];W[ib];B[be]
(;W[dg];B[de]
(;W[ff];B[ge]
(;W[gg]
(;B[if];W[ie];B[hf]
(;W[hh];B[ig];W[ih];B[jg]
(;W[kg];B[jh]
(;W[ki];B[ji];W[hj]
(;B[gi]
(;W[gj];B[fi]
(;W[fj];B[fh]
(;W[fg];B[eh]
(;W[ci];B[bh];W[ah];B[bi];W[aj];B[dj]
(;W[ej];B[dk]
(;W[dl];B[ek]
(;W[jk];B[li];W[el];B[ki]
(;W[lk];B[mj];W[nj];B[mk];W[ml];B[nk]
(;W[nm];B[om]
(;W[nn];B[oo]
(;W[np];B[no]
(;W[mp];B[mn]
(;W[mm];B[ln]
(;W[kn];B[lm]
(;W[ll];B[km]
(;W[jl];B[jn]
(;W[jo];B[hn]
(;W[ho];B[gn]
(;W[fn];B[go]
(;W[gp];B[fo]
(;W[eo];B[ep]
(;W[er];B[aq];W[do];B[bq];W[bo];B[ao]
(;W[bm];B[bn]
(;W[cm];B[dn]
(;W[en];B[cs];W[dm];B[bs]
(;W[hs];B[gr];W[gq];B[hq];W[hp];B[iq]
(;W[jq];B[ip];W[lp];B[lq]
(;W[lr];B[mq];W[nq];B[os]
(;W[qs];B[pr];W[pq];B[qq]
(;W[rq];B[qp];W[qo];B[ro]
(;W[rn];B[so]
(;W[sl];B[rm];W[qm];B[ql];W[pk];B[qj]
(;W[rj];B[pj];W[oj];B[oi];W[ni];B[oh]
(;W[og];B[nh];W[mh]
(;B[ng]
(;W[nf];B[mg];W[lg];B[mf]
(;W[me];B[lf]
(;W[kf];B[le]
(;W[ob];B[nc]
(;W[nd];B[oc]
(;W[pc];B[od]
(;W[ne];B[pg];W[pe];B[ph]
(;W[rh];B[qg]
(;W[rf];B[rg]
(;W[sh]C[success. RIGHT])
(;W[sf];B[sd]))
(;W[rg];B[rf]))
(;W[qg];B[rg]))
(;W[pe];B[ne]))
(;W[od];B[pc]
(;W[qc];B[pb])
(;W[pb];B[qc])))
(;W[oc];B[nd]
(;W[ne];B[pg]C[white can't take the liberty at P16 and connect the O15 group]
)
(;W[od];B[ne])))
(;W[nc];B[ob]))
(;W[le];B[kf]))
(;W[lf];B[me]
(;W[le];B[ne])
(;W[ne];B[le])))
(;W[mg];B[nf]
(;W[ne];B[mf]C[atari])
(;W[mf];B[ne])))
(;B[pg];W[ng];B[ph];W[rh];B[qg];W[rf];B[rg];W[sh]C[Black dies either way.]
))
(;W[nh];B[og]
(;W[ng];B[pg])
(;W[pg];B[ng]C[atari])))
(;W[pj];B[oj]))
(;W[rm];B[qm]))
(;W[so];B[rn]C[atari]))
(;W[qp];B[qo]))
(;W[pr];B[pq]))
(;W[mq];B[nq]))
(;W[ip];B[lp]))
(;W[gr];B[gq]))
(;W[dm];B[en]))
(;W[dn];B[cm]
(;W[cl];B[cs]C[this will lead to a ko later which white cannot win]
)
(;W[dm];B[bl])
(;W[bl];B[cl])))
(;W[bn];B[bm]
(;W[bl];B[cl])
(;W[cm];B[cs]C[white is unable to take the liberty at B8])))
(;W[do];B[er]))
(;W[ep];B[eo]))
(;W[fo];B[gp]))
(;W[go];B[fn]
(;W[en];B[fo])
(;W[fo];B[en]
(;W[eo];B[dn])
(;W[dn];B[eo];W[do];B[ep]
(;W[gp];B[er])
(;W[er];B[gp]
(;W[hp];B[gq])
(;W[gq];B[hp]
(;W[hq];B[ip])
(;W[ip];B[hq])))))))
(;W[gn];B[ho]
(;W[go];B[hp])
(;W[hp];B[go]
(;W[fo];B[gp]
(;W[gq];B[ep])
(;W[ep];B[eo]))
(;W[gp];B[fo]))))
(;W[hn];B[jo]))
(;W[jn];B[jl]))
(;W[km];B[ll]))
(;W[lm];B[kn]))
(;W[ln];B[mm]))
(;W[mn];B[mp]))
(;W[no];B[np]
(;W[mp];B[nq])
(;W[nq];B[mp])))
(;W[oo];B[nn]
(;W[no];B[mm])
(;W[mn];B[mm])))
(;W[om];B[nm]
(;W[mm];B[nn])
(;W[nn];B[mm]
(;W[mn];B[lm])
(;W[lm];B[mn]))))
(;W[mj];B[lk]
(;W[ll];B[mk])
(;W[mk];B[ll]
(;W[lm];B[ml])
(;W[ml];B[lm]))))
(;W[el];B[jk]))
(;W[ek];B[dl]))
(;W[dk];B[ej]))
(;W[bh];B[ci]))
(;W[eh];B[fg]))
(;W[fh];B[fj]))
(;W[fi];B[gj]))
(;B[li];W[gi];B[ki];W[lk];B[mj];W[nj];B[mk];W[ml];B[nk];W[nm]
;B[om];W[nn];B[oo];W[np];B[no];W[mp];B[mn];W[mm];B[ln];W[kn]
;B[lm];W[ll];B[km];W[jn]C[Black dies either way.]))
(;W[ji];B[ki]))
(;W[jh];B[kg]))
(;W[ig];B[hh]))
(;B[ie];W[if]))
(;W[ie];B[gg]))
(;W[ge];B[ff]
(;W[fg];B[if])
(;W[gg];B[if])))
(;W[de];B[dg]))
(;W[ib];B[hb]
(;W[ic];B[ce];W[gc];B[be]
(;W[de];B[dg])
(;W[dg];B[de]
(;W[ge];B[id])
(;W[ff];B[ge]C[atari])))
(;W[gc];B[ic];W[id];B[ce])))
(;W[ga];B[af]))