Problem	404
Created	2001-02-17
Name	Dosetsus Problem
Source	Igo-Hatsuyo Ron
Rating

Difficulty	9 dan
Average Solve Time	307 secs
User Attempts	30 / 2761
Solve Ratio Rating	6 dan
	rating history

Dosetsu`s Problem:
The hardest go problem ever constructed.
It took a group of students approximately 1000 hours to find the solution.

Please forgive me if I`ve missed any variations.
Good luck!

(;GM[1] FF[4] AP[Hibiscus:2.1] SZ[19] ST[3] ;C[Black to win the game... Ultra Difficult!!!] PL[B] AB[aj][ak][al][am][bd][bf][bm][bp][bs][ce][co][cp][cr][de][dh][di][dn][ek][el][em][ep][fc][fe][fj][fn][fo][fq][hb][il][ko][lb][lc][ld][le][lj][lk][me][mf][mi][mn][ni][nr][ns][oe][of][og][oh][oi][oo][os][pe][ph][pi][pl][pp][pq][pr][ps][qh][ql][qm][qq][ra][rh][rk][rm][sh][sk][sp][sq] AW[ah][ap][ar][bg][bj][bn][cd][cg][cj][cn][df][dg][dk][dl][en][eq][ff][gg][hc][hg][hi][hm][hp][ib][ir][jb][jd][jj][jk][jl][jm][jn][ke][kg][ki][kp][lg][lp][mb][mp][mr][ms][nd][ng][nj][od][oj][ok][on][op][or][pf][pj][qa][qc][qe][qj][qo][qp][rb][re][ri][rl][rn][ro][rq][si][sl][sm][sn][so] ;B[po] MN[1] ;W[rr] ;B[qk] ;W[ml] ;B[ll] ;W[mm] ;B[lm] ;W[nn] ;B[no] ;W[mo] ;B[ln] ;W[pn] ;B[qn] ;W[rp] ;B[ol] ;W[nl] ;B[nm] ;W[om] (;B[mj] ;W[nk] LB[nk:20][rj:A];B[rj] ;W[qi] ;B[np] ;W[rs] ;B[sr] ;W[oq] (;B[mq] ;W[lr] ;B[lq] ;W[kr] ;B[kq] ;W[jp] ;B[jq] ;W[jr] ;B[iq] ;W[hq] ;B[gr] LB[gr:37];W[hr] ;B[ip] ;W[jo] ;B[io] ;W[ho] ;B[in] (;W[hn] ;B[im] ;W[hl] ;B[ik] ;W[hk] ;B[ij] ;W[hj] ;B[ii] ;W[ih] ;B[ji] ;W[kj] ;B[jh] ;W[kh] ;B[jg] ;W[jf] ;B[ig] ;W[hh] ;B[if] ;W[ie] ;B[hf] ;W[he] ;B[gf] ;W[ge] (;B[fg] ;W[ef] ;B[fh] (;W[hs] ;B[ee] ;W[cm] ;B[an] ;W[bo] ;B[ao] ;W[aq] ;B[bi] ;W[ai] ;B[bh] ;W[ag] ;B[bk] ;W[ck] ;B[bl] ;W[cl] ;B[ak] ;W[aj] ;B[bl] ;W[ao] ;B[am] ;W[bk] ;B[al] ;W[rg] LB[rg:92][pd:A];B[pd] ;W[pc] LB[pc:94][mc:A];B[mc] ;W[nb] ;B[la] ;W[qg] ;B[dj] ;W[nc] LB[nc:100][eg:A];B[eg] ;W[mg] LB[mg:102][cf:A];B[cf] ;W[ne] ;B[nf] ;W[kb] LB[kb:106][af:A];B[af] ;W[ka] LB[ka:108][dm:A];B[dm] ;W[kc] LB[kc:110][ch:A];B[ch] ;W[kd] LB[kd:112][ci:A];B[ci] ;W[pg] LB[pg:114][br:A];B[br] ;W[ma] LB[ma:116][bq:A];B[bq] ;W[qd] LB[qd:118][as:A];B[as] ;W[sg] ;B[bm] ;W[an] ;B[al] ;W[md] LB[md:124][ak:A];B[ak] ;W[lf] LB[lf:126][bl:A];B[bl] ;W[nh] ;B[am] ;W[bm] ;B[al] (;W[pk] ;B[mk] ;W[gb] ;B[fb] ;W[fa] ;B[ea] ;W[ga] ;B[gc] ;W[ha] ;B[eb] ;W[fr] ;B[er] ;W[fs] ;B[es] ;W[gs] ;B[gd] ;W[gq] ;B[fp] ;W[gj] ;B[fi] ;W[hd] ;B[nq] ;W[oq] C[Play at ?? if you dare...] LB[oq:154][ak:??];B[ak] C[RIGHT Congratulations!] )(;W[li] ;B[nq] C[And black will win easily.] )(;W[nq] ;B[mq] C[And (beleive it or not) White will lose by 2 points.] ))(;W[rg] C[If White play} ?> </TABLE> ? } ?> </TABLE>ing race by one move.] ;B[ks] ;W[qg] ;B[pd] ;W[pc] ;B[la] ;W[mg] ;B[hs] C[etc...] ))(;B[nq] C[Sorry, this move made you lose the capturing race in the corner.] ;W[oq] ;B[qr] ;W[or] ;B[op] ;W[oq] ;B[or] ;W[ss] ;B[sq] ;W[qs] ))(;W[im] ;B[nq] ;W[oq] ;B[hn] ;W[gn] ;B[go] ;W[gm] ;B[hs] C[white's lower group is dead.] ))(;B[nq] ;W[oq] ;B[mq] ;W[lr] ;B[lq] ;W[kr] ;B[kq] ;W[jp] ;B[jq] ;W[jr] ;B[iq] ;W[hq] ;B[ip] ;W[jo] ;B[io] ;W[ho] ;B[in] ;W[im] (;B[qr] ;W[hn] ;B[qs] ;W[ss] ;B[sq] ;W[op] )(;B[hn] ;W[gn] ;B[go] ;W[gm] ;B[hr] ;W[gr] ;B[hs] ;W[gq] )))(;B[nk] ;W[mk] (;B[mj] C[Sorry, you've just filled in a very important liberty.] )(;B[pm] C[Wasting ko-threaths is always bad.] ))(;B[pm] C[Sorry, wasting ko-treats isn't a smart thing.] ))