(;SZ[19]TM[6 hours]RE[W+R]BR[9d]WR[9d]PB[Kitani Minoru]PW[Go Seigen \[Wu\]]PC[Tokyo ]EV[The 1st Japan Strongest Deciding Matches]C[Go Seigen (Wu) vs. Kitani

(The 1st Japan's Strongest Deciding Matches)

Black: Kitani Minoru, 9d

White: Go Seigen (Wu), 9d

Date:  April 14-15, 1957

Place: Tokyo]PL[B]DT[1957-04-14]US[tasuki];B[qd]C[(* Before WWII, in Japan, the most popular stars in sports were led by Futabayama of sumo \[Japanese wrestling\], Kawakami of baseball, Boriguchi of boxing, and Kimura Meijin of shogi.  While in Go, the most honorable, at the top of the world, were none other than the discoverers of "new opennings", Kitani Minoru and Go Seigen \[Wu\].

(* \[Now it's post-war time.\] Those famous stars \[excluding Wu and Kitani\], at one time or another, have either retired or faded, and only the home run king of baseball, Kawakami, is still able to live up with his fame; he is a rarity.

(* But Wu, since traveling to Japan in 1928 at the age of 14, has held the highest honor in Go, never faded in 30 years. He is truely a genius that would appear only once a few hundred years in Go history. *)];W[dc]C[(* Comparing with competitions in which outcome may be decided in a short burst or a split of second, a Go game takes much longer battles to yield a winner and a loser.  This may have told us why Go players' professional careers are longer than that of other sports. *)]
;B[pq]C[(* After WWII, Kitani's record was down for a while, but since he was promoted to 9 dan last year \[1956\], his once unbeatable form has re-appeared.  Recently he posted an astonishing record of 14 wins and 5 losses.  In major tournaments like the Highest Rank Deciding Matches, Honinbo Matches, and Tokyo Newspaper sponsored Championship Matches, he all recorded triumphs. *)];W[oc]C[(* Is the once overwhelming "Wu-Kitani Era" re-emerging?  Gradually recovered, rising giant Minoru Kitani, challenges Go Seigen for the first time in 13 years.  This balanced struggle is indeed the most remarkable post-war battle since the Wu-Fujisawa 10-game series. *)];B[cp]C[This is the first game between Kitani 9 dan and me \[me = Wu\] after the War.

Before the War, we had a 10-game series when we were 7 dans; later, we also played 4 games.  I remember these 4 games were three games in the Grant Meet (Nihon Kiin's \[Japanese Go Association\] ranked players tournament) and one game sponsored by Yomiuri Newspaper.  Finally in 1944 \[during the War, that is\], we met again in the ranked players tournament when we were 8 dans.  This game now is my first against Mr. Kitani in 13 years.];W[po]C[This game is played in Tokyo Chiyoda District Kioi Street's Fukudake Inn on April 14-15, 1957.  At the same time, the game between Sakata Eio 9 dan and Takagawa Honinbo 8 dan \[another of Strongest Deciding Matches\] is also held here.  That game of theirs will end with Sakata 9 dan, playing Black, winning by 4 points.];B[pp]C[B #7 \[Q4\] is Kitani 9 dan's unique move; other players rarely play it, but Kitani 9 dan has used it a few times in openings like the 1-3-5 \[R16-Q3-C4\] of this game.

B doesn't want to play B\[a\] so that W would play \[Q4\] to form the "avalanche shape", so \[Q4\] move applies the proverb "opponent's key point is also my key point."]
(;W[oo]C[W #8 extending upwards is solid.

If W #8 extends downwards \[R5\] --- see variation
];B[qo]C[B #9 hane is big.]
(;W[qn]C[W #10 certainly.

Compare with joseki in variation diagram]
(;B[ro]C[B #11 --- variation B S4];W[qg]C[W #12 normally plays W\[a\].

Kitani 9 dan said in his post-game review that, if W\[a\], B had prepared to play B\[b\].

In the situation shown in this game, W #12 does have various ways to play.];B[pe]C[B #13 of course.];W[qj]C[W #14 is also normal.];B[ep]LB[eq:a]LB[rn:a]C[B #15 is a big point on the board.

Had #15 been played B\[a\], W would certainly ignore it \[tenuki\] and play W\[b\].];W[cf]C[W #16 is also a big point that cannot miss.  This point and B #15 \[E4\] are miai \[counterbalance moves of same weight\].]
;B[kc]C[B #17 is an extremely good point.

Next move, W #18, is a difficult one. \[difficult to find a good spot, that is.\]
]
(;W[oe]C[W could have chosen N17 (see variation). Instead, W adopted \[P15\] to attach.]
(;B[pg]C[So B simply pressing at \[Q13\] is tesuji. B P14 is bad (see variation)
]
(;W[pd]C[W #20 to squeeze here is a good move.];B[qe]C[B #21 certainly.]
(;W[of]LB[qc:a]C[W #22 extending at \[P14\] is good. For hane at 'a', see variation.
]
(;B[pf]C[B #23 has no choice but \[Q14\] (see variation).];W[qc]C[W, as a result, gets #24 and ...];B[rc];W[qb]C[... #26 to settle the corner.  This local fight thus comes to a pause.];B[hc]C[If B\[a\] for #27, that would be a good point too, but then W would certainly play W\[b\], and \[b\] is a point that cannot be missed.

B #27 as played \[H17\] is an extremely big point.]LB[ic:a]LB[qh:a];W[qh]C[But then W gets #28 \[R12\] key point, and W is in a form to attack B.]
;B[og]C[If B #29 tenuki \[plays elsewhere\], W\[a\] and B big chunk is captured.]LB[nh:a];W[rn]C[W thus finally gets #30 \[S16\].  During this period of conflict, B never got a chance to play \[S16\].];B[np]C[B #31 is absolutely the only move.

If B tenuki \[plays elsewhere\], when Wa\[O3\], B has to defend with Bb\[S3\]; letting W to seal in B with sente is unbearable.]LB[rq:a]LB[nq:a]
(;W[iq]C[J3 absolutely (see variation)];B[pi]LB[qi:a]LB[oi:a]C[B #33 \[Q11\] on the one hand prevents W\[a\] in previous variation, on the other hand aims at B\[b\] cut.]
(;W[lq]C[If W #34 plays at the right side \[around R11\], it would be slow.

See variation for what could happen if Black next plays away from lower right corner.]
(;B[mq];W[lp];B[no]C[...\[Also\] B now has #37 to get out, aiming at \[a\] cut at the same time.

At this critical point, W made a mistake in the next move.]
(;W[nn]LB[mn:a]C[In any case, #38 plays in a wrong direction. Here W should \[T5\] first
(see first variation).

If W\[a\] next, it would *not* be a sente move, thus B wouldn't answer it (see second variation)
];B[qi]C[Because of W's mistake at #38 \[O6\], B finally gets sente, and with that, B cleverly turns to play \[R11\].];W[ri]C[If W can get sente here, W would have W\[a\]-B\[b\]-W\[c\] sequence to extend W's territory at the right side.]LB[oi:a]LB[oh:a]LB[ph:a];B[rj];W[rk]C[Had B #41 \[S10\] played \[a\] cut, W would have atari with \[b\].  With this kind of shape, "capture the cut stone" is common sense.]LB[rg:a]LB[rh:a]
;B[pj]LB[rg:a]LB[sj:a]LB[rh:a]C[It would be awkward for B #43 to atari at \[a\], forcing W\[b\], then B\[c\] to get two W stones. \[Imagine, for example, after B\[c\], W plays \[Q10\].\]]
(;W[sj]C[W #44 however --- If W connects directly at \[R9\] see variation.];B[qk];W[rj]
(;B[pk]C[To here, W is pressed to a low position.  This is the fault of W #38 \[O6\]. Therefore, it has become an opening favoring B.

See variation for possible Black attack.]
(;W[mc]C[If White plays elsewhere, see variation.];B[fc]C[B #49 \[F17\] is very good.

At first sight, \[a\] seems to be the real big point for #49.  But if B\[a\], W will certainly presses at \[F17\].  Then the B teams at upper and right sides would yet have enough eyes, and with two "floating" teams, B would be difficult.

Moreover, now with #49, B creates an opportunity for B\[b\] to attack W.]LB[ce:a]LB[ck:a];W[ck]C[Since B gets \[F17\], \[C9\] big point is left for W.];B[gq]C[And then B #51 \[G3\] becomes clearly the next biggest point.

B #51 could also consider to play at \[N6\] \[see an earlier reference at move #47\], but that would make it complicated, so B #51 "cashes in" with some territory first. \[I guess Wu is saying, since B is leading, no need for him to make it complex.\]];W[mo]C[W\[a\] for #52 is a correct \[text\] move, but if W does play \[a\], it would be no threat to B's corner \[see reference at move #38\].

Also, if W\[a\], B\[b\] to force W\[c\], and B\[d\] would give B a clear lead.

Therefore, even though \[N5\] for W #52 is not solid, W doesn't have many choices.  This is again the fault of #38 \[O6\].

W #52's purpose is to force B repond here, so W can get sente.
]LB[pn:a]LB[pm:a]LB[mn:a]

(;B[lr]C[If B ignores here, see variation. Therefore, B #53 \[M2\] and ...
];W[kr];B[mr]C[...\[and\] #55 \[N2\] are necessary.

In short, in order to get sente, W has to make a move like #52 \[N5\], although it would leave some weak point.];W[nj]LB[mn:a]C[W #56 is the key point to attack.  No matter what, if W doesn't stick with this B group, W will have no way to win.

#56's purpose is to gain opportunities to protect cut at \[a\] by attacking B team.  Conversely, B can adopt two difference attitudes, either harder or softer, when he chooses his next plays.  In short, this is the first crisis of the game. 

]
(;B[nk]C[Black could attack more directly with Q7 but this is not satisfactory (see first variation). Black N8 would give W a headache (see second variation). However, Black chose O9.];W[mk];B[nl]C[...\[and\] #59.  This is of course the most solid way to play, but ...];W[mj]C[...\[but\] after W #60 connects, W has somewhat achieved his goal of attacking B.]
(;B[oj]C[A cut at \[P6\] by B would start a large-scale battle (see variation)];W[so]TR[po]TR[oo]C[W #62 is to gain with sente before sacrificing \[P5\]\[Q5\].];B[rq];W[ml];B[nm]
(;W[mm]C[(* The big spot at the left side is the key point concerning the trend of both sides' growth.  Here we can see how both sides deliberate intensively over this situation. *)];B[on];W[mn];B[pn]LB[qm:a]C[To here, although W loses two stones, but he gets a spectacular outside thickness in *sente*.  W has managed to gain back what he lost on #38 \[O6\].
]
(;W[cn]LB[ql:a]LB[rl:a]LB[qm:a]C[After B #69, *if* W can gain with \[a\], seemingly sente, then turn to left side, that would be even better for W \[than to turn to left directly\]. See variation.

\[But Wu said that \[R7\] wouldn't be a sente move for W now.  I thought, "Hey, why bother? \[C6\] is big, get it first anyway." But the fact is, in this level of games, *every* point is important.  If one passes by a sente move, it could be not sente later.\]

Anyway, W finally gets the chance to occupy the big spot at \[C6\], and thus escapes from the previously disadvantageous situation.

At the right side, if B\[b\], W\[c\] cut would take care of it.];B[qm]C[Since W got the big spot at the left edge, letting B to gain here with #71...];W[rm];B[ql]C[...and #73 is unavoidable.];W[rl];B[co]C[B #75 is the way to solidify the corner.  Of course, even if B doesn't play this move, the corner has no problem for now.  But later, when the outside situation changes, then there is a possibility that W will cast in W\[a\].  So B #75 now to prevent it.]

(;W[bn]LB[er:a]LB[bp:a]LB[bq:a]LB[dn:a]C[W #76 extending downwards decides the growth of both sides' territory.  W\[a\] extending upwards would be yielding and passive.

\[Also,\] W #76 aims at W\[b\]-B\[c\]-W\[d\].
];B[ce]C[B #77 is long-waited severe tesuji.];W[de]C[W #78 absolutely *cannot* play at \[C16\] to give in.];B[cd]
(;W[df]C[W #80 to connect is a strong move.];B[dd];W[ed];B[ec]C[Since W #82 \[E16\] blocked, B #83 of course has no choice but to cut, looking forward to a deciding fight.];W[cc]C[W #84, too, is the only move.];B[bc];W[bb]
(;B[bf]
(;W[bg];B[bd]C[B #89 only move.]
(;W[af]C[The only choice.];B[ab]
(;W[ba]C[This move leads to a ko. If White #92 at 'a', there is a more difficult ko for White.];B[ae]C[B #93, and the huge ko that would determine the result of this game has started.];W[be];B[ee];W[fd];B[bf]C[After B #97, W can't find an appropriate ko threat anywhere on the board, how to save such a dangerous situation?];W[ag]C[Under the current circumstances, W #98 is the choice when there's no choice.];B[eb];W[cb]
(;B[cg]C[B #101 cuts directly. Good.

See variation.];W[gd]LB[be:a]C[W #102.  This point absolutely cannot be passed by.

If W\[a\] for #102, B would follow with \[G16\], and that's a ko threat for B.];B[bh]C[B #103 to pull these few stones \[W \[A13\] etc.\] into the ko is rather unexpected.

This this the second crisis of the game. \[The first was back at move #56.\]

(* Later there will be detailed analysis for B #103.

(* As for this ko, what are the best moves?  Please study it by yourself, then compare your conclusion with B #103. *)];W[be];B[rf]C[B #105 threatens a W team that is worth about 50 points.

(* W to answer a move here seems to be unquestionable, since it's hard to imagine that W would sacrifice such a big group.  But Go Seigen 9 dan's strategies are often unexpected --- *)];W[ad]C[W #106 unhesitatingly finishes the ko.

\[He did!  I couldn't believe it. :)\]]
(;B[sh]C[B #107, and the right W team is dead.  However, I think with the moyo at the middle, W has more than enough to compete with B.

Therefore, B #103 \[B12\] was a questionable move.

In this picture, W G16 \[marked\], extending out, gave W's central moyo a big boost in thickness.  So B's best policy at this point was to shift the emphasis to the middle, damaging W's attempt to control the center. Consequently, B #103 should play as in variation.
]TR[gd]
(;W[en]C[W #108 wrong order.  Before this, W should play W\[a\], forcing B\[b\], *then* jump at \[a\] (see variation).

Afterwards if B\[c\] to do a shallow invasion, W\[d\] to fence. This way, from the global point of view, it's a better trade for W.
]
(;B[hd]C[Although B #109 is a correct move \[under normal circumstances\], under the current situation, B is better to adopt the following play.
];W[he];B[ge]LB[if:a]LB[ie:a]C[If B\[a\] for #111, it would just help W to get \[b\].

B #111 cuts is to apply here some techniques directly, looking for some chances to turn it around.];W[ie];B[fe];W[ac]
(;B[ej]C[B #115 too deep.

Since B has gone so deep into W's zone...];W[gj]C[...W #116 has no choice but to surround B and try to kill.];B[el]LB[ig:a]LB[fi:a]LB[gh:a]C[B is better to play \[a\] for #117.  Then if W\[b\], B\[c\] to seek a living path in another direction.];W[fm]C[This B #117 and W #118 exchange \[E8-F7\] is worth a reconsideration \[by B\].  Since inside the influence of W thickness, B #117 could easily lead himself to a trap that he cannot escape. Besides, after W plays #118, when B later tries to invade from the bottom, it will be different. \[It's harder for B to invade from the bottom now, clearly.\]];B[gh]C[(* Since it has developed to this situation, the only way for B to win is to desperately find a way to save this team.

(* On the other hand, if W fails to capture B, W would lose.  Therefore W has no choice but to fight his hardest.  It's make-or-break.  As shown, an inspiring and heartbreaking fight has begun. *)]
;W[fi]C[Kitani 9 dan's given time has completely consumed \[each player is given 10 hours; Kitani's clock should show 9 hours 59 minutes, saving the last minute for byo-yomi\], and he doesn't have sufficient time to deliberate.];B[eg];W[fh];B[fg];W[hg];B[gg];W[hh];B[fl]LB[gi:a]LB[gk:a]C[If B #127 plays at \[a\], W would counter with \[b\].

Even if W let B run away towards center, W's right side has a metal-solid wall, and B eventually cannot escape.];W[di]
;B[cj];W[dh]
(;B[cl];W[dk];B[dl];W[do];B[dj];W[bk]C[(* W #132-#134-#136 \[D9-D5-B9\] are related tesuji.  After #134 \[D5\], B's \[lower left\] corner becomes shaky. *)]TR[do]TR[dk];B[gi];W[fj];B[ek];W[bl]
;B[hi]LB[dp:a]C[(* The middle-game fight has come to a most critical point.  It's such a close and intense melee at the center, B has no chance to defend the weakness at \[a\]. *)];W[dg];B[ji];W[jd]LB[jc:a]C[If B ignores W #144, W\[a\] would be unbearable.  No matter how urgent the situation at the center is, B has to answer here.];B[jc];W[kh];B[jh]C[(* Now every move by Kitani 9 dan is under the sound of byo-yomi. *)];W[kf];B[hj]
;W[hl];B[il];W[im]C[(* Starting from B #115 \[E10, the move that Wu commented as "too deep"\], it has been Kitani 9-dan's unique "invading strategy." Often this strategy \[to let opponent form a big frame, then to live a group in this frame\] would terrify the opponent... *)];B[hk]C[(* ...However in this game, W's zone is as solid as a flawless castle, and it's really hard for B to achieve what he has looked for.  Besides, Kitani 9-dan is now short of time, which puts him at a more disadvantageous position. *)];W[hm];B[lh];W[ki];B[kg];W[lg];B[jg];W[le]
(;B[kj]C[After W #160, if B tries to make an eye starting with G14, then W would adopt the techniques shown in the variation to destory B's \[other\] eye at the bottom \["bottom" here is meant to be around \[K10\]\].];W[li];B[jk]
(;W[hf]C[W #164 connects to destory the eye at \[a\] is the safest way. Thus, no matter how B struggles, B cannot live now.
];B[]C[White wins by resignation.

Time given: 10 hours apiece

Time consumed:

Black: 9 hours 59 minutes

White: 6 hours 26 minutes])
(;W[jl]C[(* If W hastily atari at \[K8\]...*)];B[ih]C[(* B \[J12\] (sente)... *)];W[hf];B[ij]C[(* ...and B \[J10\] makes a ko. *)
]))
(;B[gf];W[hf];B[ef];W[jl];B[ik];W[jj]C[...W \[K10\] to deprive an eye from B is a severe tesuji.  With this move, the chances for B to live become slim.];B[kj];W[li];B[jk];W[kk];B[ij];W[ih]C[...W \[J12\] denies another eye for B...]
;B[kl]C[...even if B \[L8\]...];W[lk];B[jm]C[...and \[K7\] to capture a W stone...];W[io]C[...W \[J5\] jumps, and B is still not alive.

\[Blood!\]]))
(;B[gm]C[\[If B \[G7\] hane...\]];W[gn];B[em];W[fn]C[After W \[G6\] and \[F6\]...];B[dn]C[...even if B cuts at \[D6\]...];W[dm];B[do];W[dl];B[dj];W[bj]C[W has \[D7\], \[D8\], and \[B10\] to live at the bottom.  Then...]
;B[hn];W[ho]C[...W \[H5\] also hane, and it works. The result: B is unsuccessful.
]))
(;B[hh]C[In instead B H12...];W[jh];B[fg]C[...\[and\] \[F13\], this would become a large-scale death-life problem.  To live inside W's surronding stones is probably quite difficult, and in fact, under this situation, even if B doesn't try to struggle to live here, he could instead invade from the lower side to somewhat damage W's territory -- and that could be enough.  But to give up the upper portion is a difficult decision to make, since it's difficult to be sure that B would gain enough from below.]))
(;B[ie]C[B \[J15\]...];W[jd];B[jc];W[hf]C[...W probably would play \[H14\]...];B[he];W[gf];B[jg];W[ih];B[fn];W[fm];B[gn]C[Then \[F6\] and \[G6\] to reduce W territory...]
;W[eo];B[fp]C[...to here, B should be quite content with this picture.  Besides, the B territory at upper side is also increased.

Hence, \[J15\] was the key point that neither side should miss.]))
(;W[ie];B[en]TR[ic]C[if B doesn't play J17 but jumps at E6
];W[ib]C[W has \[J18\] tesuji...];B[ic];W[jb];B[kb];W[jc];B[jd];W[hb];B[gc];W[kd]C[...to here, it's difficult for this B team to live.]
))
(;C[Back to the situation after W #102 \[G16\].]PL[B]AB[ae][bf]AE[ad][bh][be][rf];B[hd]LB[bh:a]C[\[Wu's opinion on B #103\] is that B shouldn't play \[a\], but instead to rise at \[H16\]. ];W[be]C[When W \[B15\] captures...];B[sh]LB[ad:a]LB[bh:a]C[...B \[T12\] threats. (If W\[b\] now to finish the ko, B would play \[S14\] to kill W's team.  But this \[situation\] is different from the actual game.  The B\[a\] move in actual game is now at \[H16\] key point, and B is clearly better \[if W continues with the way he played in actual game -- \[A16\] finishes the ko and sacrifices team at right\].) ...]
;W[rf]C[...so W \[S14\] has to answer the threat of \[T12\]...];B[bf]C[...B captures...]
(;W[dg]C[...when W \[D13\]...
];B[re]C[...B forces another W move here...];W[sg];B[ge]C[...then from \[G15\] to...];W[fe];B[ff];W[ef];B[gf]C[...\[to\] \[G14\]...];W[be];B[gc]
;W[ee];B[bf];W[ch]C[...after W \[C12\] captures one B stone...];B[dn]C[...B \[D6\] hane...];W[dm];B[en]C[...and \[E6\] extends.  Later W needs two moves to clean up the \[upper left\] corner.  This way, W's moyo is greatly shrunken.])
(;W[ad]C[Here, if W throws in at \[A16\] \[in reference 1, it's played at \[D13\].\]...];B[ac];W[be];B[re];W[sg];B[bf];W[om];B[op];W[be];B[pc];W[ad];B[od]
;W[aa];B[nd]C[...to here, it becomes a big exchange.  B is still better.
])))
(;B[gd]C[If W \[G16\] atari instead...];W[fe]C[...after W \[F15\]...];B[cg]C[...*then* cuts at \[C13\]...];W[be];B[rf];W[rg];B[bf];W[dg];B[ch];W[be];B[ff]
;W[ge];B[bf];W[hd];B[gc];W[be];B[he];W[gf];B[bf];W[hf];B[bh];W[be];B[sg]C[When B \[T13\] to threat...]
;W[ad];B[sh]C[...when B \[T12\] to kill the big W team at the left...];W[fn]C[...W \[F6\] big jump and with the huge moyo at left, although W sacrificed a big team at left, he has enough to counter B.

\[The key that W *could* sacrifice a huge team at right is that W's upper left is now very thick, thus his huge moyo looks very promising.\]
]))
(;W[cb];B[ba];W[ca];B[da]C[Ko.]))
(;W[ac]C[If White hane];B[ab];W[aa];B[ae];W[ch];B[db];W[cb];B[eb];W[ag];B[af];W[ca]C[White makes a seki in gote, a big loss.])
(;W[ab]C[If White sagari...];B[cg];W[bh];B[ee];W[fd];B[ef];W[dg];B[ge]C[The two White stones are captured.]TR[fd]TR[ed]))
(;W[ad]C[If White peeps];B[be];W[bg];B[ab];W[ac];B[db];W[cb];B[ca];W[bd];B[ba]C[Ko.];W[aa]LB[rf:a]C[Black has a big threat at 'a' so this ko is no good for White.]
))
(;B[bd]C[Connecting doesn't work.];W[ac];B[bf];W[ad];B[be];W[bg]C[B is dead.]))
(;W[dd];B[bf];W[bg];B[cg];W[df];B[bh];W[be];B[ag];W[bd];B[dj]C[Black has sacrificed two stones to destroy White's centre moyo.]))
(;C[\[W \[B6\] aims at \[B3\]...\]]PL[W]AW[bn];W[bq]C[\[When W \[B3\]...\]];B[cq]C[If B blocks at \[C3\]];W[bp]C[...W \[B4\] up to...];B[bo];W[ao];B[br];W[ar]C[...\[up to\] \[A2\] are extremely big ending moves.
]
))
(;W[qm]C[Suppose W plays \[R7\] to force B to respond...];B[cm]C[...but B ignores (tenuki) and plays \[C7\], the big point at left side...
];W[om]C[...say W would then \[P7\]...
];B[op];W[pm]C[With \[Q7\], White seems to have captured the upper-right black
group since it appears that Black cannot make two eyes.];B[rf];W[rg];B[rb];W[ra];B[ph]
;W[nh];B[ng];W[lf];B[sf];W[sb];B[sd];W[re]C[Now Black has only one eye but];B[sh];W[sg];B[rl];W[ql];B[sl];W[sm]
;B[qf];W[rh];B[ol]C[Now black has the second eye since White cannot atari at Q8. If White tries Q8, he loses his group!

This way, not only B lives here completely, also he already gets the big point \[C7\] at the left.  Therefore, W's hope to gain with sente at \[R7\] is invalid.]))
(;W[mn]C[If W \[N6\] connects...
];B[pm]C[...after B \[Q7\] peep...];W[pn]C[...W \[Q6\] connects...];B[cm]C[...B gets the big point at the left.  Besides, W leaves a leak at \[N7\].  Thus this W shape is thin.]))
(;B[on];W[om];B[mn];W[nm];B[ml];W[mm];B[ll];W[ph];B[oh];W[oi];B[li];W[nh];B[ng]
;W[mh]C[...to here, the situation is quite complicated; the outcome is hard to predict for B.

\[So B chose to play \[P10\] instead of a fierce cut at \[P6\].\]]))
(;B[pm]C[\[Assume B is to adopt the hardest tactic against W \[O10\]...\]
B \[Q7\] peeks...
];W[pn];B[nk];W[mk];B[ml]C[...\[N8\] hane...
];W[nl];B[nm];W[ok];B[ol]C[...however, after B \[P8\] atari...
];W[mm]
;B[nk]C[...after B \[O9\] to take the ko...
];W[op]C[...W has a ko threat at \[P4\] \[assumably more to come\]...];B[lm]C[...so B has to atari first, then...
];W[mn];B[nl];W[oq];B[or];W[nr];B[pr];W[nq]LB[mh:a]LB[nh:a]LB[ng:a]LB[rq:a]C[...\[up to\] \[O3\].  Thus both sides made an exchange.  Since W can next get either \[a\] or \[b\], this result is good for W.

For example, if B plays \[a\] next to protect the corner, W can play W\[b\]-B\[c\]-W\[d\] "double hane", and B's thickness formed by \[O8\] \[the move that connected the ko\] is gone.
]
;B[]C[\[Say B ignores the corner and plays around \[O13\]...\]
];W[rq]C[W tosses in a stone at \[S3\]...];B[rr];W[rp];B[qq];W[qp];B[sq];W[so];B[qs]C[...to here, although B is not really killed, but letting W to eat two stones \[previously at R5-S5\] in *sente* is a big loss.

\[Conclusion, W is better\]])
(;B[nl]C[B \[O8\] \[= headache :-)\]...]
(;W[ph]C[...if W \[Q12\] and...
];B[oh];W[oi]C[...\[and\] \[P11\] to cut...
];B[ni]C[...B \[O11\] to...];W[oj];B[mi];W[mj];B[lj];W[lk];B[mm]C[...\[to\] \[N7\] peek and...
]
;W[kk];B[mn]C[...\[and\] \[N6\] cut, W would be farily thin.  So W can't hastily cut with \[Q12\] and \[P11\] \[marked stones\].

(After this shape, if W\[a\], B would of course give up the five stones. \[Q9 five stones\])
]LB[ok:a]TR[ph]TR[oi])
(;W[ol];B[om]C[...B starts with \[P7\] up to...];W[pl];B[nm];W[ql];B[ni];W[mi];B[nh];W[mn];B[nk];W[ok];B[mj]
;W[oj];B[li];W[mk];B[lj];W[lk];B[kk];W[ll]TR[nk]TR[nl]TR[om]TR[nm];B[cm]C[...\[but\] B gets the big point at \[C7\], and it's an easy situation for B.

\[Conclusion: like in variation 2, B comes out better with \[O8\] -- after W \[O10\].\]]
)))
(;B[];W[rq];B[qp];W[nr]C[...W \[O2\] another peek.

\[Wu didn't explain further.  The way I see it, W now has either \[N2\] or \[P4\], plus the "bomb" at \[S3\], it *is* a headache to B.\]
]))
(;W[]C[Suppose W doesn't play N17...];B[nd]C[B immediately peeks at O16...];W[od];B[nc]C[...and blocks with O17.  These two moves \[O16-O17\] concern the base of both sides; extremely big.
]))
(;PL[B]AB[pk];B[mn]C[\[...with N6...\]];W[nm];B[pm];W[pn];B[rl]C[To here, although B doesn't quite separate W groups, B is now able to attack this big W team when time comes.]))
(;W[qk];B[rh]C[...B *would* get the two W stones...];W[sj];B[rg]TR[qk]TR[pj]C[(* In other words, it's a big difference between with or without B \[Q10\] forcing W \[R9\]. *)

\[So W \[R9\] should \[T10\] capture directly, which W did for his #44.\]
]))
(;W[so]C[W hane sente to gain (this play's purpose is to sacrifice \[P5\]\[Q5\] \[marked\] two stones when B cuts at \[Q6\])...];B[rq];W[qk]
(;B[pn]C[If B cuts now...];W[pm];B[on];W[om]C[...W \[Q7\] and \[P7\] to sacrifice two stones...];B[nn];W[fq]C[...then turn to \[F3\], an extremely good point...])
(;B[gq]C[B, instead of cut \[Q6\], plays \[G3\] here...];W[nn]C[...then W \[O6\] and...];B[mn];W[nm]LB[ng:a]C[...\[and\] \[O7\] are appropriate moves.  Now, W\[a\] becomes a severe attack.]))
(;C[\[Suppose W has played \[N6\] and B ignores it (tenuki)...\]]PL[W]AW[mn][nn];W[rq]C[If W \[S3\] and ...
];B[qp];W[qr]C[...\[and\] \[R2\]...];B[pr]C[...B plays \[Q2\] and there is no play at the corner.

\[Therefore, \[N6\] is not sente.\]]))
(;B[qi]C[If B pushes and cuts...];W[ri];B[rj];W[rk]C[W would atari from this side \[S9\], sacrificing the two stones \[R12 and R13\] above.
]))
(;PL[W]AW[lq];W[op];B[oq];W[nq]C[W can \[P4\] and \[O3\] to cut.

\[This shows the importance of B #35 at N3.\]
]))
(;W[oi]C[If W plays \[P11\] to exchange with B \[N13\]...];B[mg];W[iq];B[nd];W[od];B[nf]C[B would have \[O16\] peep and \[O14\].  Now B's both sides are settled, and B becomes thicker.]))
(;B[qh]C[If B still wants to capture one W stone with \[R12\]...];W[qc];B[rc];W[rb]C[...W would have \[R17\] and \[S18\] double hane...];B[qb];W[pc];B[rd];W[ic];B[ke];W[ie]C[...W first gains with \[J17\] and \[J15\]...]
;B[kg];W[sb]LB[ph:a]LB[rh:a]LB[rg:a]C[...then settles the corner with \[T18\].  This way, W is better.

Besides, after this shape, W also has aji of W\[a\]-B\[b\]-W\[c\], aiming to reduce B's liberties from outside, thus sealing B inside.
]))
(;W[qc]C[If W #22 hane with \[a\] ---];B[of];W[ne];B[rc];W[qb];B[qh]C[When B \[R12\] captures one W stone, B gets a good shape.
]))
(;W[pf]C[W \[Q14\] to wedge in seems to be severe, but will it have a satisfactoy result?]
(;B[of]C[White can hope Black will play the sequence starting with P14 ];W[qf];B[od]C[\[P16\] atari to get out would be a mediocre move.];W[ne];B[nd];W[me];B[md];W[le]LB[pc:a]C[It's certain to get here. This way, not only W enlarged his moyo to the biggest extend, but also W left some aji at \[a\].  If so, W is of course better.  However, Black has a better way to deal with Q14.
])
(;B[od]LB[nd:a]LB[of:a]C[B simply \[P16\] to wedge in is tesuji. Then if W\[a\], B\[b\].  This exchange would be in favor of B.

So W \[Q14\] is not good.
])))
(;B[of]C[If B \[P14\] hane...
];W[ne]C[W would happily extend at \[O15\]...];B[pg];W[qf]
(;B[pf]C[It ends up with this shape; clearly, \[P14\] for B \[#19\] would be a mistake.

Another way to look at this situation is to change the order of the moves (see variation diagram).])
(;C[Think of this W \[R14\] and B \[Q14\] exchange.  If B played #19 at \[P14\] as shown in the previous variation diagram \[at move #18\], it would be like B now does an exchage of B\[a\] and W\[b\] \[which is clearly bad\].  That's why \[Q14\] for B #19 would be wrong.
]LB[ne:a]LB[of:a]TR[qf]TR[pg]TR[pf]PL[W]AB[pf]AE[ne][of])))
(;W[mc]C[W could have chosen N17 (see variation). Instead, W adopted \[P15\] to attach.];B[pc]C[Then B would certainly play \[Q17\]...];W[ic]C[After that, if W \[J17\] to press...];B[ke];W[me];B[ie];W[gd];B[lg]C[We can then imagine a picture up to here.  W would look thin, so I didn't adpot this way to play.
]))
(;B[rp];W[ro];B[qp]C[The leak of W to the right is almost covered, so B \[S4\] is not as good as \[S5\], the way actually played.]))
(;C[\[Japanese editor, Mr. Katsumoto, gives us another angle to look at the way two players have played the corner so far.\]]PL[B]AE[oo][pp][qo];B[qo];W[pn];B[pp];W[qn];B[ro]C[(* The way two players have played so far is similar to this joseki. *)
]))
(;W[qo];B[oo];W[on];B[no];W[nn];B[mo]C[The sequence to here would be certain.  Not only B will have a peek at
'a' (followed by W 'b' connecting and B 'c' extending), W's \[P6\] and \[O6\] playing on line 6 is also unsatisfactory.
]LB[qm:a]LB[pn:a]LB[pm:a]))