(;GM[1]FF[4]CA[UTF-8]AP[CGoban:2]ST[2]RU[Japanese]SZ[19]KM[0.00]PW[Sakata Eio 9d]PB[Go Seigen 9d];B[qd]CR[qd]C[Go Seigen (Wu) vs. Sakata (The 1st Japan's Strongest Deciding Matches)Date: May, 1957Place: Matsuyama];W[pp]CR[pp]C[This game is played near a hot spring in Matsuyama, Shikoku (one of the main Islands of Japan). Meanwhile, the referee is Fujisawa Hosai 9-dan. Shikoku is a place where Go is very popular. This time, the arrival of five 9-dans at the same time (should be four 9-dans; Takagawa is still 8-dan then) is a rare chance for Go fans, thus the entusiastic greetings from the fans were unprecedented.];B[cd]CR[cd]LB[dc:A]C[COMMENTARY BY GO SEIGEN HIMSELFBlack creates a mukai komoku (two komoku stones facing each other). This is a fuseki I have used quite often recently.When I was 4- or 5-dan, I'd sometimes play at A. This is only the difference in personal inclination, nothing deep.](;W[ec]CR[ec]LB[jc:C][oc:A][ed:B][dq:D]C[If White played at A instead. when Black played B and White C, Black would occupy D in the lower left.In such an arrangement, White's current move is better than A. This is common sense in fuseki (see variation).];B[oc]CR[oc]C[Black plays kogeima shimari (kogeima: small knight's move, shimari: corner enclosure). This is the most solid move for Black.];W[eq]CR[eq]C[Up to here, this opening also appeared in the games when I played Iwamoto Kaoru 8-dan and Takagawa Honinbo. In those games, they were White, too.(Before, ina game between Sakata 9-dan (White) and Takagawa Honinbo, the exact same opening appeared as well. Perhaps because of this, in this game, both sides spent little time to get to this point.)](;B[hd]CR[hd]LB[gd:A]C[Black could also consider playing A for a one-space pincer. In a game between me and Takagawa Honinbo, I played this way (see variation) and Sakata 9-dan played this way (see second variation) in Honinbo Sen.In short, under this arrangement, there are various ways like one-space or two-space pincers.];W[ef]CR[ef]C[This and the following Black move...];B[cg]CR[cg]C[...are the simplest joseki.];W[qi]CR[qi]LB[qj:B][cp:A]C[This is the biggest fuseki point.Of course, the shimari at A is also big, but under this current situation, it's difficult for Black to play there himself (see variation).Besides, a move at B would be extremely good for Black, and White prevents that here. From this standpoint, this is indeed the best point.](;B[cq]CR[cq]LB[cp:A]C[Since the approach at C4 is not very good (see variation), Black chooses to play here.];W[do]CR[do]C[Naturally.];B[co]CR[co](;W[dn]CR[dn]LB[cn:A]C[White cannot play at A, so this is the only move (see variation).];B[cn]CR[cn]C[Extending is the only move for Black.];W[dm]CR[dm]TR[cq]C[At this point, it's obvious that Black's marked stone has added a force in the corner, which is clearly better than C4.];B[nq]CR[nq]LB[pn:A][ip:C][jq:B]C[When Black approaches here, White has many ways to respond, and the choice is difficult.If White simply jumps to A, Black would immediately extend to B or C. If so, it would be an easy game for Black.](;W[oq]CR[oq]LB[lq:A]C[White chooses to play kosumi-tsuke...White could also play at A... (see variation)];B[np]CR[np];W[kp]CR[kp]C[...and then to extend from the wall on the left.The purpose of this sequence is to prevent Black from getting into the corner AND to create a pincer attack on the Black stones. That is, White is trying to make moves on both sides. A greedy move.];B[po]CR[po]C[This is the urgent point.](;W[oo]CR[oo]LB[qo:A]C[White could have played at A, but chose this hane instead, initiating a violent fight.The reason that White plays so violently is because ladders to the upper left are good for White.(see variation for a White move at A instead)];B[op]CR[op]C[White has read out that after Black plays here...];W[pq]CR[pq]LB[qo:A]C[...the severe move at A is not as effective since the ladder works for White.From a strategical standpoint, since Black gained in the lower left corner, it's natural for White to force Black to fight inside of White's sphere of influence - White hopes to gain in the process.];B[qo]CR[qo]C[Black sagari (extend downwards) and accepts the challenge to a fight. The result of this battle would directly affect the oucome of the game. Thus we reach the first climax of the game.](;W[no]CR[no]LB[on:A][rp:C][rq:B]C[Based on the shape, it seems natural for White to play at A. However, that would give black the opportunity to play at B.If White played here at C instead... (see variation)];B[mo]CR[mo]C[Black exchanges N5...];W[mn]CR[mn]C[...for N6. Neither side can give in an inch.];B[nr]CR[nr](;W[rq]CR[rq]LB[lo:A]C[If White were to play this move at A... (see variation)]PL[B];B[lo]CR[lo]LB[om:A]C[Black extends...](;W[pn]CR[pn]LB[om:A]C[...and White hane. Normally, he would play at A, but in this situation he cannot do so... (see variation)](;B[rp]CR[rp]LB[qn:A]C[This is a tesuji.If Black plays at A instead... (see variation)](;W[qp]CR[qp]LB[qm:B][qn:A]C[White has no choice but to play here, and later live with R2.If he plays A or B instead... (see variations)](;B[ro]CR[ro]LB[rn:A][sp:B][qr:C]C[Can Black play A instead?If White plays at B right after and then plays C to live, of course A is better for Black.However, if White doesn't play B and instead plays C directly to live, Black would have some trouble (see variation).];W[qr]CR[qr];B[om]CR[om]C[This is the most urgent point.](;W[on]CR[on]LB[pm:A]C[White must connect, and Black gains in sente.If White tries something else at A... (see variation)];B[ql]CR[ql];W[pm]CR[pm]C[White pushes. He has no other way but to determinedly hang on.];B[pl]CR[pl];W[ol]CR[ol]C[A violent fight beings.];B[nm]CR[nm]C[Such close combat so early in the opening is rarely seen in today's high-dan games.];W[nn]CR[nn];B[ok]CR[ok]C[Black atari...];W[nl]CR[nl];B[ko]CR[ko]C[...and extend. This combo is delivered in good order. After White's push and cut, this picture is expected.];W[nk]CR[nk];B[or]CR[or]LB[rk:D][rl:C][qm:A][rm:B]C[There is nothing deep about this move, but consider:Later, after the sequence from White A to Black D (of course White can't play this right now), this move would no longer be sente. Therefore, to make this exchange and gain while it's still sente is good.];W[pr]CR[pr];B[oj]CR[oj](;W[jp]CR[jp]LB[rn:A]C[White has no choice but to play here.If he were to play at A instead... (see variation)];B[km]CR[km];W[nj]CR[nj];B[oi]CR[oi]C[These moves are certain. This move sealed the first day of the game.];W[lq]CR[lq]C[Against this move...];B[jo]CR[jo]C[...Black has a good reply.](;W[ip]CR[ip]LB[mp:A]C[White cannot play at A... (see variation)];B[mq]CR[mq]LB[lr:A]C[This is the best way to protect the cut. Later, Black can gain an eye in sente at A.];W[lm]CR[lm]LB[rn:A]C[This move also aims at the tesuji at A.];B[ln]CR[ln]LB[rn:A]C[Not only does this move prevent the tesuji at A (shortage of liberties for White), it also helps to make an eye.The most efficient move.];W[kl]CR[kl];B[jm]CR[jm]LB[ll:B][mm:C][rn:A]C[Black absolutely CANNOT atari at B, since White's reply at C would free up precious liberties and the tesuji at A would work again.];W[lr]CR[lr]C[This move is extremely big.From a profit standpoint, it's an anti-sente move worth 6-7 points (compare it with a sente Black hane here), and it has the purpose of taking away Black's eyes and attacking Black.A huge point.];B[jl]CR[jl]LB[qg:F][ki:E][jj:D][kj:C][jk:B][kk:A]C[This move puts White in a dilemma.If White plays A, giving rise to the sequence up to D. All of the pushes here would be unbearable to White, and when White is finally forced to extend again at E, Black would take F, an extremely good point.](;W[pg]CR[pg]LB[of:B][qf:A][rk:C]C[White temporarily puts the left side on hold, and plays here on the right.If White played at A instead, after the cap at B White would be in trouble.Also, it might be tempting to play at C first, but... (see variation)];B[qj]CR[qj]LB[rn:A]C[This is the key point for both sides' eyeshape; absolutely impossible to pass by.Also, this move removes the aji at A.];W[ll]CR[ll]LB[rn:A]C[Since the aji of A is gone, Black could cut here if White fails to play. So White connects here at M8.];B[hn]CR[hn]LB[fq:A]C[Black plays the key point of both sides. This point acts as a hinge for White's moyo, and if he had played here the difference would be tremendous.In addition, this move creates a tesuji at A.After this move, the violent fight comes to a pause. Based on the result up to now, White didn't quite get what he had hoped for. Black is better.];W[rj]CR[rj];B[rk]CR[rk];W[pj]CR[pj]C[A severe method, initiating a ko fight.];B[pk]CR[pk]LB[pi:A]C[This ko is light for White, since even if Black wins the ko and captures at A, it wouldn't be much of a loss for White.];W[qk]CR[qk]LB[rl:B]C[On the other hand, if White wins teh ko and cuts at B, it would be a heavy burden to Black.So if Black loses this ko, it would be huge.];B[sr]CR[sr]C[Black must take this ko seriously.];W[sq]CR[sq];B[qj]CR[qj];W[rd]CR[rd]C[This is a point White wants to get even if it's not used as a ko threat.Excellent timing.];B[qe]CR[qe](;W[re]CR[re]LB[qk:A][rl:B]C[If White used this move to recapture at A instead, Black would play here to capture the White stone.Then, even if White cuts at B next, White wouldn't have enough threats and would lose the ko (see variation).];B[rc]CR[rc]C[White has invested quite a bit here now, so when Black hane...];W[qf]CR[qf]C[...this move cannot be omitted.];B[pi]CR[pi]C[It is now a fair trade to both sides.];W[pe]CR[pe]C[Even though White lost the ko...];B[pd]CR[pd];W[oe]CR[oe]C[...White rushes out, and should be satisfied.Since White was fighting within Black's influence, getting such a result is quite decent.];B[mc]CR[mc]LB[nc:A]C[This point is a must.If Black tenuki (plays elsewhere), a White move at A would be severe.];W[qc]CR[qc]LB[sd:B]C[Great timing.If White tenuki, Black would immediately hane at B and the difference would be big.];B[qb]CR[qb];W[sc]CR[sc];B[rb]CR[rb]C[White gains in sente.](;W[cp]CR[cp]LB[cm:A]C[White's purpose here is to start a violent fight, in order use the thickness to gain the best results.If White at A instead... (see variation)](;B[dp]CR[dp]C[Black cannot block from the bottom... (see variation)];W[bp]CR[bp]C[When White sagari (descends)...];B[dq]CR[dq]C[...Black connects. White's next move is difficult.](;W[bq]CR[bq]LB[cm:A][ep:B]C[Based on the actual results of the game, this move might be worth reconsidering... (see variation for alternate moves at A or B)];B[ep]CR[ep]C[Certainly Black plays here.](;W[fp]CR[fp]C[The only move (see variation).White plays here...];B[fq]CR[fq]C[...to exchange for Black F3.Then...];W[cm]CR[cm]LB[hq:A]C[...White finally captures the two stones.This way, a Black move at A lacks the same punch... (see variation)](;B[gp]CR[gp];W[hq]CR[hq]C[White is settled, and the fight in the lower left draws to a temporary conclusion.Locally, White got the corner and gained, but to lose sente is questionable. That is to say...];B[rg]CR[rg]C[Black gets to play here...];W[rf]CR[rf];B[qh]CR[qh]C[...and here, taking not only a big gain in territory, but also depriving White of eyeshape. Even though he lost a bit in the left corner, this should satisfy Black.The is the result mentioned earlier, when White 96 was brought into quesiton.];W[md]CR[md]LB[le:A]C[Another questionable move. Because of this move, Black's top side solidifies.A looser move at A would have been tougher to handle.];B[ld]CR[ld]C[The hane is the only move, no other choice.];W[nc]CR[nc]C[This is a severe tesuji.];B[nb]CR[nb]C[Black can only respond from below; no other choice.];W[nd]CR[nd];B[lc]CR[lc]C[White gained in sente, but Black is solidified.];W[le]CR[le]TR[md]C[This hane...];B[ke]CR[ke];W[kf]CR[kf]C[...and this one, too, are tesuji moves calculated when White played the marked stone.];B[lf]CR[lf];W[me]CR[me];B[lg]CR[lg]LB[hb:B][je:A]C[White might have expected Black to play at A instead, but even with A there is a hole for a White invasion at B. Therefore, A would be slightly slow for Black.A strong move!];W[ob]CR[ob]C[A clever yose move...];B[lb]CR[lb];W[qg]CR[qg];B[rh]CR[rh](;W[mg]CR[mg]C[A good move (see variation).];B[ed]CR[ed]LB[mh:A][nh:B]C[If Black played at A here, aiming to split White and attack both groups, White would also hane at B, and Black wouldn't get what he wants.This shows Sakata 9-dan's extraordinary skills. At first glance it seems like both White groups are under attack, but after N13, even an expert like Go Seigen could not find a strong move to continue the attack.](;W[dc]CR[dc]LB[fd:A]C[The only move.If White hane at A instead... (see variation)];B[cc]CR[cc];W[cb]CR[cb];B[bb]CR[bb];W[gc]CR[gc];B[dd]CR[dd];W[hc]CR[hc]TR[ob]C[Now White regrets the marked move a little, because Black's response is hurting White here at the top.];B[jf]CR[jf]C[A clever move. It seems the ladder works for White, but...](;W[da]CR[da]LB[ib:B]TR[kf]C[...White cannot save the marked stone (see variation).Instead, a White move here is necessary, because after Black captures the marked stone, without D19, a move at B would destroy White's eyeshape.];B[kg]CR[kg];W[mh]CR[mh]C[This move finally connects White's top and bottom groups.];B[cj]CR[cj]C[But now Black leads in territory.];W[fd]CR[fd]C[If White plays endgame in the normal way now, he would not have enough points.Therefore, with this move...];B[fe]CR[fe];W[ee]CR[ee]C[...and this cut, he hopes to find a chance to turn it around.];B[ge]CR[ge];W[ch]CR[ch]TR[fd]C[This is the tesuji White was aiming at with the marked move.];B[dh]CR[dh](;W[cf]CR[cf]LB[dg:A]C[This move is better than a cut at A... (see variation)];B[bf]CR[bf]LB[be:B][bg:A]C[If Black plays at A instead, White B would kill the corner.];W[bg]CR[bg];B[dg]CR[dg];W[be]CR[be];B[df]CR[df](;W[af]CR[af]LB[ce:A]C[White has no choice but to capture the stone here...There is a simple variation if White plays at A instead, but... (see variation)];B[ce]CR[ce]C[When Black atari...];W[di]CR[di]C[...White hane...];B[ci]CR[ci];W[de]CR[de]C[...and cuts, creating a ko. White's goal now is to seal Black from the outside.];B[bf]CR[bf];W[na]CR[na];B[mb]CR[mb];W[cf]CR[cf];B[bc]CR[bc]C[Black gets to play here because the ko is not "tight" for Black (his four stones are not under atari).];W[eh]CR[eh]LB[bh:A][ei:B]C[If White connects at A instead, Black will B because the ladder works for him.];B[bf]CR[bf];W[pb]CR[pb];B[pc]CR[pc];W[cf]CR[cf];B[bh]CR[bh];W[eg]CR[eg]C[White seals Black in.];B[bf]CR[bf];W[od]CR[od]C[If the ko fight continues on the left, White wouldn't expect any immediate gain, so it's more urgent to settle the weak group on the right side first.];B[qc]CR[qc];W[cf]CR[cf];B[ch]CR[ch];W[ba]CR[ba];B[bf]CR[bf];W[fj]CR[fj];B[ej]CR[ej]C[This is the key point to attack White.];W[ei]CR[ei];B[dj]CR[dj];W[gi]CR[gi];B[fk]CR[fk];W[cf]CR[cf]LB[hj:B][gk:A]C[White cannot play A because Black would peep at B and White would be in danger.];B[ah]CR[ah]C[A tesuji.](;W[hj]CR[hj]LB[ag:C][jj:A][gk:B]C[A shape move. Now A and B are miai.It would not do White any good to resist at C... (see variation)];B[gk]CR[gk];W[jj]CR[jj];B[bl]CR[bl]C[This moves presses...];W[bm]CR[bm]C[...and forces White to respond. It's quite painful for White, but he has no choice but to answer.];B[br]CR[br]C[Then B2...];W[ar]CR[ar];B[cs]CR[cs]C[...and C1 are big yose moves.](;W[el]CR[el]C[White MUST play here.If he doesn't... (see variation)];B[gj]CR[gj];W[ii]CR[ii];B[hh]CR[hh];W[hi]CR[hi];B[ki]CR[ki];W[jk]CR[jk];B[ib]CR[ib];W[gd]CR[gd];B[he]CR[he];W[ic]CR[ic];B[jb]CR[jb];W[jc]CR[jc]C[Although all three of White's groups are now settled, White is trailing behind in territory.];B[kc]CR[kc];W[ab]CR[ab];B[bf]CR[bf];W[fb]CR[fb]LB[hb:A][ac:B][ag:C]C[White would get more points here at A, but would lose the big yose move at B.That is, when White later tries to continue the ko fight and forces Black to play C, White B wouldn't be there, and White wouldn't gain anything.];B[cl]CR[cl];W[fo]CR[fo];B[gq]CR[gq];W[go]CR[go];B[hr]CR[hr];W[ho]CR[ho];B[hl]CR[hl];W[ir]CR[ir];B[hp]CR[hp];W[iq]CR[iq];B[er]CR[er]C[If Black played G2 here instead, White would play E2 and the Black gropu would not be clean.];W[gr]CR[gr];B[fr]CR[fr];W[sb]CR[sb]C[This is a sente move worth 4 points or more.];B[pa]CR[pa];W[hs]CR[hs];B[hb]CR[hb];W[gb]CR[gb](;B[ag]CR[ag]C[This is worth 7 points or more (See variation where White plays here first).];W[hg]CR[hg];B[jd]CR[jd];W[gm]CR[gm];B[hm]CR[hm];W[ig]CR[ig];B[fi]CR[fi];W[fh]CR[fh];B[io]CR[io];W[fm]CR[fm]LB[eo:A]TR[fo][go][ho][fp]C[If White doesn't play here, Black would push in at A and the four marked stones would be captured.If White tried to save the four stones, the entire group would die.];B[rr]CR[rr];W[rs]CR[rs];B[lj]CR[lj];W[ph]CR[ph];B[mi]CR[mi];W[nf]CR[nf];B[oh]CR[oh];W[og]CR[og]LB[li:C][ni:B][ik:D][kk:A]C[After this move, even if Black cuts at A, White can save both groups with B. If Black then plays C, White lives with D.];B[jh]CR[jh](;W[lh]CR[lh]C[The only move... (see variation)];B[ih]CR[ih];W[gh]CR[gh];B[ji]CR[ji];W[qn]CR[qn];B[rn]CR[rn];W[sp]CR[sp]C[With this move, White is trying to live above (he has a sente capture at N7).];B[ik]CR[ik];W[ij]CR[ij];B[dl]CR[dl];W[am]CR[am];B[as]CR[as]C[Even if Black doesn't start a ko fight here, he is still better. Since he has more ko threats, though, he makes this move.];W[bs]CR[bs];B[ni]CR[ni]C[White resigns here. He didn't achieve his goal after starting a fight in the lower right corner, and his situation grew worse and worse.Time given: 10 hours apieceTime Consumed:Black - 4 hours 28 minutesWhite - 9 hours 59 minutes])(;W[ih]CR[ih]C[White would love to play here but...];B[kk]CR[kk]C[...after the cut...];W[ni]CR[ni];B[ji]CR[ji]C[...White is dead.]))(;LB[ag:A]C[If Black fails to play at A...]PL[W];W[cf]CR[cf]C[White will start a yose sequence...];B[ag]CR[ag];W[ac]CR[ac];B[bf]CR[bf];W[bd]CR[bd]C[...to here. This is why White played G18 isntead of H18.]))(;W[]C[If White tenuki here...];B[am]CR[am];W[an]CR[an];B[aq]CR[aq]C[...after a throw-in, the group does not have enough eyes.]))(;W[ag]CR[ag]C[If White fights against Black's tesuji...];B[ad]CR[ad];W[bd]CR[bd];B[ac]CR[ac];W[aa]CR[aa];B[bf]CR[bf]C[It is a loose ko for Black (White needs to ignore three ko threats to win).]))(;W[ce]CR[ce]C[If White connects, it will be more peaceful but...];B[de]CR[de];W[bd]CR[bd];B[bc]CR[bc];W[bi]CR[bi];B[ci]CR[ci];W[bh]CR[bh];B[bj]CR[bj];W[af]CR[af]C[...White will live in gote and...];B[jj]CR[jj]C[...Black will get to jump to K10. He will get a considerable amount of territory on the outside, and White cannot be content.]))(;W[dg]CR[dg]C[If White cuts...];B[bg]CR[bg]C[...Black would go for the following exchange...];W[di]CR[di];B[eh]CR[eh];W[ci]CR[ci];B[ei]CR[ei];W[dj]CR[dj];B[ej]CR[ej]C[To here, although Black loses one stone, White loses a equal amount, so Black is not bad.]))(;W[kg]CR[kg]C[If White rescues this stone...];B[kh]CR[kh]C[Black happily plays here...];W[jg]CR[jg];B[mh]CR[mh]C[...because it gives him a chance to hane. Now this hane works, and White is hurt.]))(;W[fd]CR[fd]C[If White hane here...];B[dc]CR[dc]C[Black would get the benefit in the corner.At this moment, the goal of the fight is to get the benefit of the corner.]))(;W[ng]CR[ng]C[If White plays here instead...];B[mh]CR[mh]LB[nf:A]C[...Black gets to seal up White in sente. If White doesn't play at A now, Black will do so and kill the group.]))(;B[hq]CR[hq]LB[fp:1][fq:2]C[After the marked exchange, if Black plays here...];W[gq]CR[gq]C[...White has G3.];B[fr]CR[fr];W[gr]CR[gr];B[gp]CR[gp];W[hp]CR[hp];B[fo]CR[fo];W[go]CR[go];B[fp]CR[fp];W[hr]CR[hr]C[White is safe.]))(;W[cm]CR[cm]C[White cannot block here. If he does...];B[hq]CR[hq]C[...Black will play a severe tesuji.];W[gq]CR[gq]C[White has no other choice but to exchange...];B[hp]CR[hp];W[hr]CR[hr];B[ir]CR[ir];W[gp]CR[gp];B[iq]CR[iq];W[go]CR[go];B[ho]CR[ho];W[fr]CR[fr];B[hs]CR[hs]C[...and after this, White still needs another move to completely capture the Black stones. This exchange is favorable to Black.]))(;W[cm]CR[cm]C[If White blocks here instead...];B[bq]CR[bq];W[bn]CR[bn];B[ap]CR[ap];W[bo]CR[bo];B[er]CR[er];W[fr]CR[fr];B[fq]CR[fq];W[gq]CR[gq];B[fp]CR[fp]LB[ri:A]C[...White gains in sente with the sequence up to here, and can next play at A.This would be the strongest way based on the results.])(;W[ep]CR[ep]C[What if White blocks from this side instead?];B[bq]CR[bq];W[cm]CR[cm];B[bo]CR[bo];W[bn]CR[bn];B[ap]CR[ap]C[Black gets two stones...];W[cc]CR[cc]C[...in this situation, this can be called a strong move, and White can expect the following sequence...];B[bc]CR[bc];W[cf]CR[cf];B[dc]CR[dc];W[dg]CR[dg];B[ed]CR[ed]C[First an exchange...];W[hl]CR[hl];B[ik]CR[ik];W[gj]CR[gj]LB[bf:B][bm:A]C[...then White tries to extend the moyo on the left. But after this, White cannot hope to get as big a stomach as he imagines.Also, Black still has the capture at A and another large endgame move at B. Clearly, this situation is in favor of Black.]))(;B[bp]CR[bp]C[If Black blocks here instead...];W[dp]CR[dp];B[br]CR[br]C[...White gets a thicker outside in sente. Black absolutely cannot give in like this.]))(;W[cm]CR[cm]C[If White blocks here...];B[er]CR[er];W[fr]CR[fr];B[dr]CR[dr];W[dp]CR[dp]C[After this move, Black can actually tekui to get some other big points!];B[]C[Say Black tenuki here...];W[cp]CR[cp];B[bp]CR[bp];W[bo]CR[bo]C[If White cuts...];B[bq]CR[bq];W[bn]CR[bn]C[...White would get two stones in GOTE and would be trailing globally.]))(;W[qk]CR[qk]C[If White recaptures instead...];B[re]CR[re]C[... would take the stone in the corner.];W[rl]CR[rl]C[When White cuts...];B[qj]CR[qj]C[...Black takes back.];W[cp]CR[cp];B[bp]CR[bp];W[qk]CR[qk];B[rr]CR[rr];W[rs]CR[rs];B[qj]CR[qj]LB[lp:A]C[And when Black takes the ko back again, White cannot find another suitable ko threat.Threats like A would be too small.]))(;W[rk]CR[rk]LB[pg:A]C[If White plays here before A...];B[rl]CR[rl];W[qk]CR[qk]C[...White gains sente but...];B[pk]CR[pk];W[pg]CR[pg]LB[rn:A]C[The aji at A disappears.White cannot play this way.]))(;W[mp]CR[mp]C[If White cuts...];B[lp]CR[lp];W[mq]CR[mq];B[kq]CR[kq];W[kr]CR[kr];B[jq]CR[jq];W[mr]CR[mr];B[ip]CR[ip]C[...Black captures two stones and White's prospects in the middle are destroyed. White loses big.]))(;W[rn]CR[rn]C[If White plays here...];B[qn]CR[qn]C[...Black would sacrifice the stones with R6...];W[qm]CR[qm];B[rm]CR[rm](;W[sn]CR[sn];B[mm]CR[mm];W[ln]CR[ln];B[rk]CR[rk];W[sp]CR[sp]LB[rm:B][sn:C][jp:A]C[...and the sequence would continue to here.Although White has captured the five stones, Black has a huge move at A, and so is still good.If White tries to do better in this sequence by playing B instead of C... (see variation)])(;W[rl]CR[rl]C[If White cuts instead of extending...];B[sn]CR[sn]C[...Black would live first.];W[pk]CR[pk];B[sp]CR[sp];W[qk]CR[qk]C[When White is forced to capture the two stones...];B[sr]CR[sr]C[...Black jumps into the corner, killing it. This way, not only is this a huge loss, also White will have no way to attack Black's group on the lower side.])))(;W[pm]CR[pm]C[If White tries to extend instead...];B[pl]CR[pl]C[Black blocks...];W[ol]CR[ol];B[nl]CR[nl];W[on]CR[on];B[ok]CR[ok];W[rm]CR[rm];B[rl]CR[rl]C[...and although White captures four Black stones, Black forms a ponnuki in the middle and White's loss is greater than the gain.The proverb says "a ponnuki is worth 30 points," and the power of this shape is clearly seen.]))(;B[rn]CR[rn]C[If Black connects with S6...];W[qr]CR[qr]C[White could play here directly.](;B[ql]CR[ql]C[If Black jumps out...];W[nm]CR[nm]LB[pk:A][lq:B]C[...White protects the cutting point.Next, A and B are miai for White. Black is not good.])(;B[om]CR[om]C[If Black peeps...];W[qm]CR[qm]C[...White plays a good move with R7.];B[ql]CR[ql];W[rm]CR[rm];B[on]CR[on];W[nn]CR[nn];B[rl]CR[rl];W[ln]CR[ln];B[ko]CR[ko];W[pm]CR[pm]LB[ol:B][pl:A]C[Now, if Black tries to seal white in with A, White cuts with B and the ladder works for White.])))(;W[qn]CR[qn]C[If White tries to block black inside, he is pushing too hard.];B[rn]CR[rn];W[ql]CR[ql];B[rm]CR[rm]C[First Black increases his liberties...];W[rl]CR[rl];B[rr]CR[rr]C[...then he plays S2 and wins the semeai.])(;W[qm]CR[qm]C[If White plays a little bit loose at R7...];B[rm]CR[rm];W[rl]CR[rl];B[rn]CR[rn]LB[ql:A][qq:B]C[The cut at A and the wedge at B are miai for Black, so he is still good.]))(;B[qn]CR[qn]C[If Black plays here instead...];W[pm]CR[pm];B[qm]CR[qm];W[pl]CR[pl]C[...White would just extend to build up a solid wall, sealing Black inside in the process. Even if Black lives inside, it would still be very unfavorable to him.]))(;W[om]CR[om]C[If White jumps instead...];B[pl]CR[pl]C[...Black also jumps.];W[pm]CR[pm];B[qm]CR[qm];W[ql]CR[ql]C[If White tries to cut...];B[qk]CR[qk];W[rl]CR[rl];B[rk]CR[rk];W[rm]CR[rm];B[qn]CR[qn];W[pk]CR[pk];B[ol]CR[ol];W[nl]CR[nl];B[ok]CR[ok];W[pj]CR[pj];B[rn]CR[rn]C[White fails since the ladder to the upper left works for Black.]))(;W[lo]CR[lo]C[If White hane instead...];B[qq]CR[qq]C[...then Black kills the corner with R3.];W[qp]CR[qp];B[rp]CR[rp];W[rq]CR[rq];B[pr]CR[pr];W[qr]CR[qr];B[or]CR[or];W[qq]CR[qq];B[ro]CR[ro]C[Black would win this semeai (capturing race).]))(;W[rp]CR[rp]C[If White plays here to protect the corner...];B[ro]CR[ro]C[...Black blocks...];W[qp]CR[qp];B[nn]CR[nn]C[...and Black throws out a net. Although the net doesn't work...];W[on]CR[on];B[om]CR[om];W[pn]CR[pn];B[pm]CR[pm];W[qn]CR[qn];B[rn]CR[rn];W[qm]CR[qm];B[ql]CR[ql];W[rm]CR[rm];B[rl]CR[rl];W[so]CR[so];B[no]CR[no];W[sn]CR[sn];B[nm]CR[nm]C[...Black gets to sacrifice the stones to seal White in from the outside. This way, White's moyo becomes thin in the face of Black's thickness.]))(;W[qo]CR[qo]C[If White plays here instead...];B[pn]CR[pn];W[op]CR[op];B[no]CR[no];W[qp]CR[qp];B[ln]CR[ln]LB[qm:A][jn:B]C[...the sequence leads to here. If White jumps to A now, Black will jump to B and reduce White's moyo.]))(;W[lq]CR[lq]LB[kp:B]C[If White pincers here...(Playing at B instead is bad, see variation)];B[qq]CR[qq]C[...Black will invade the corner.];W[qp]CR[qp];B[pq]CR[pq];W[op]CR[op];B[nr]CR[nr];W[mo]CR[mo];B[pj]CR[pj]C[To this point, although Black gains the corner and this key point as well, White's outside moyo is also remarkable. This is another choice for White.])(;W[kp]CR[kp]C[If White makes a high pincer...];B[qq]CR[qq];W[qp]CR[qp];B[pq]CR[pq];W[op]CR[op];B[mr]CR[mr]LB[jq:B][nr:A]C[...Black would play here instead of at A, aiming to invade at B.]))(;W[cn]CR[cn]C[If White plays here...];B[dn]CR[dn]C[...Black will cut, knowing the ladder doesn't work for White.](;W[eo]CR[eo];B[cm]CR[cm];W[bn]CR[bn];B[bo]CR[bo];W[dm]CR[dm];B[en]CR[en];W[bm]CR[bm];B[cl]CR[cl];W[dl]CR[dl];B[bl]CR[bl]C[White fails.])(;W[cp]CR[cp]C[If White tries this tack instead...];B[bo]CR[bo];W[dp]CR[dp];B[bp]CR[bp];W[cm]CR[cm];B[dq]CR[dq];W[ep]CR[ep];B[en]CR[en];W[dk]CR[dk];B[dh]CR[dh]LB[dc:A]C[...it turns into a violent fight. If Black next plays a kosumi-tsuke (diagonal attaching move), White would be under attack. This variation is not good for White, either.])))(;B[cp]CR[cp]C[Suppose Black approaches the lower left corner here...];W[do]CR[do];B[co]CR[co];W[dn]CR[dn]C[Up to here, the Black stones are forced into a low position on the third line on both the upper and lower sides.Therefore, enlcosing the lower left corner was not urgent for White and he played R11 instead.]))(;B[gd]CR[gd]C[In earlier games, Wu played the one-space pincer...](;W[gc]CR[gc];B[fd]CR[fd];W[fc]CR[fc];B[ed]CR[ed])(;W[ee]CR[ee];B[df]CR[df];W[id]CR[id];B[gf]CR[gf];W[gc]CR[gc])))(;AW[jc][oc]AB[ed][dq]C[Black's form looks good.]))