(;SZ[19]DT[1812-04-02]PB[Nakano Chitoku (Yasui Senchi)]PW[Honinbo Genjo]RE[B+R]US[tasuki];B[qd];W[dc];B[cp];W[pq];B[ce];W[eq];B[iq];W[ci];B[cm]

(;W[ei]C[ White could also play at "a".];B[gc];W[ed];B[jc]C[ Black 11 and 13 are adequate moves.  White has spent 3 moves attacking the single Black stone, while Black is avoiding White's main punch.]
(;W[oc]C[ If White plays at "a"..];B[bc]C[ Now White has played \\t, Black wants to rescue his single stone. Black 15 is aiming to make eyes.]
(;W[bb]C[ If White plays 16 at "a"..];B[dh];W[di];B[cc];W[cb];B[eb];W[db];B[df];W[fe];B[fg];W[ch]
(;B[ff]C[ If Black plays 27 at "a"..];W[he];B[mc];W[bf];B[ee]C[ Black 31 is good. This forces...];W[fd]C[ White to answer at 32 before playing...];B[be]C[ Black 33. This is the correct order of moves.];W[oe];B[qg];W[gb];B[hb]
;W[cf]
(;B[fb]C[ If Black plays at "a"..];W[dd];B[de];W[ld];B[gh];W[if];B[lc];W[kd];B[kc];W[ih];B[fj];W[dl];B[cl]
;W[ck];B[dm];W[el];B[hj];W[io]C[ White 56 aims at attacking the unsettled Black group above. Normally, it would not be a good idea to prompt Black to play...];B[lq];W[eg];B[gf];W[id];B[jj];W[ph];B[qh];W[pi]
;B[pg];W[og];B[rj];W[em]
(;B[ef]C[ This move has intrigued players for more than 150 years, because it seems equivalent to a pass. Black 69 gives him a 50/50 chance of making an eye by capturing \\t and he is therefore a little safer. It has also been suggested that Chitku was hinting to Genjo that he was losing and should resign. If Black does not play at 69..];W[nq];B[ki];W[ik];B[ij];W[kg];B[gq];W[eo];B[cq]C[ Black 75 and 77 are to secure his territory. At this point, although White's thickness is superior, Black has more territory and Chitoku had secured enough to prevent Genjo gaining an upset.];W[qk];B[qj];W[pj]
;B[ql];W[pl];B[rk];W[qm];B[pk];W[ok];B[hg];W[dr]
(;B[mq]C[ This is a safe move. If Black answers White on the left..];W[gk];B[ig];W[jh];B[gj];W[hr]
(;B[hq];W[gr];B[ir];W[bk];B[cr];W[fq];B[nr];W[or];B[np];W[op];B[oq];W[fi];B[hh]
;W[nq];B[mp];W[qk];B[oq];W[ic];B[ib];W[nq];B[pk];W[jg];B[hk];W[qk];B[oq];W[rl]
;B[nq]C[ Since Black is sure of victory, he does not mind conceding one ko as long as he wins the other.];W[qe];B[re];W[rd];B[qf];W[qc];B[pe];W[pd];B[qe];W[bo];B[co];W[an];B[bm]
;W[am];B[al];W[bl];B[bn];W[ak];B[bp];W[pr];B[pp];W[qp];B[oo];W[qo];B[pb];W[pc]
;B[ob];W[ne];B[fn]
(;W[gn]C[ If White plays at "a".. Black therefore tries a counterattack.];B[go];W[gm];B[fo]C[ However, Black 51 and 53 crush his hopes.]
(;W[hl]C[ It is better to play at "a", but...];B[ho]C[ White now has to defend both A and B, which is hopeless.])
(;W[en];B[fm];W[fl];B[hl]C[   This is also bad for White.]))
(;W[en];B[hm]C[   If White plays at 1, Black will play at 2 and White would get no points in   this area and may lose his single stone \\t.]))
(;B[gr];W[jq]
(;B[jr];W[ir]C[   Black cannot play at 1 because White will play 2 and 4.])
(;B[ir];W[jr]C[     This result is also unfavourable to Black.])))
(;B[cr];W[hr];B[hq];W[kr];B[lr];W[kq];B[kp];W[lp];B[jq];W[ko];B[jp];W[mq];B[jr]
;W[mr];B[ks]
(;W[lo]C[   White will sacrifice two stones to strengthen his outside wall. Whjite 16   could also be played at "a".])
(;W[jo])))
(;B[tt];W[ik];B[ij];W[gi]C[   If Black plays elsewhere, White can attack strongly with 2 and 4 or   threaten Black's eye shape with A.]))
(;B[dd];W[fb]C[   If Black plays at 1, White will be happy to take the single stone with 2.   White is now securely alive, while Black still has the worry that, if   White gets a move at A, he will still have to get another eye.]))
(;B[cg];W[eg];B[ef];W[ff];B[eh];W[fh];B[dg];W[gg]C[   Black would be sealed in.]))
(;W[df];B[cf];W[dg];B[cb]C[   Black will live easily.]))
(;W[cd];B[od]C[   If White plays 1, Black makes a shimari at 2, giving the single stone   away.]))
(;W[cd];B[de];W[fd];B[ei]C[   White 1 to Black 4 would be recommended when Black has not played at \\t.]))
