Thread: White 21
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Old 2014-02-23, 23:59   #21
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"Richard B. Woods"
Aug 2002
Wisconsin USA

22×3×641 Posts

Something I forgot to do earlier: count tempos needed to achieve the subgoal of taking the c4 pawn. This may seem unnecessary after we've already laid out scenarios, but it might possibly help (me, at least :-) notice something overlooked.

(BTW, I don't recall ever having done this before the endgame phase in any previous game. I'll have to keep it in mind for possible future middlegame use.)

I'm going to count only the preparation tempi, not the actual c4 capture which should be simply a sequence of successive captures at the end.

For us:
Move N/d1 to e3, and B/g2 to f1, to have two attackers on c4: four tempi. Remove B/a6 defender if it's still there: one tempo. Total: 4-5.

For Black:
Defend B/a6, or move it: one tempo. Move N/e7, through either c8 or d5, to b6 for defending c4: two tempi. Either defend N/c6 or move it off the long diagonal: one tempo. However, Bb7 would simultaneously defend both B and N, so don't count that tempo twice. Move B/g7 to h6 for taking out our N/e3: two tempi. Total: 4-6.

However, some Black moves might interfere with other moves, such as (a) Rb6 to defend the B/a6 and also placing N/e7 on b6 to defend the c4-pawn or (b) moving Bc8 to escape attack and also moving N/e7 through c8, rather than Nd5, to reach b6. That means Black will probably not move Rb6, and must move Nd5 if the B/a6 retreats to c8.

Further, in order to retain B/g2 threats to capture a N on d5 or c6, we should leave the B/g2 where it is until the last moment, so Bf1 would be the last move of our sequence.

- -

So, how to use this?

First, on move 21:
If Black plays [B]21 ... Ra8 or Rb6[/B], then we'll (probably) have to spend the Nxa6 tempo, for a total of five.

But [B]21 ... Bb7[/B] would accomplish two things (defend B/a6, defend N/c6) with a single tempo. Then, once Black plays Nc8 or Nd5, we could remove the only remaining knight defender with Nxb7, same tempo as Nxa6 would have taken. But Black can probably avoid ever exposing the N/c6 to capture by the B/g2.

So, logical Black move 21 is [B]21 ... Bb7[/B] -- Oh, you guys already figured that out.

Move 22:
On moves 22 and 23, we can bring one attacker to bear on c4 -- the Ne3, because we want to leave Bf1 until last. So, [B]22 Bd2[/B] has merit over 22 Rf2.

Therefore, Black can't afford to waste any time bringing his N/e7 to defend c4. But 22 ... Nc8 isn't feasible because of 23 Nxb7 Rxb7 24 Bxc6+

So it'd be [B]22 ... Nd5[/B]

Now 23 Bxd5 would eliminate a potential c4 defender ... but that just would allow a different defender to appear: 23 ... exd5.
If then 24 Ne3 to attack the d5-pawn, 24 ... Ne7 defends it twice, and we could remove only one of those defenders with 25 Nxb7. Then after 25 ... Rxb7 we've basically just helped Black un-crowd his queen-side while winning no material.
We could then switch our attack to the b-pawn with 26 cxb4 axb4 27 Nc2 but 27 ... b3 squelches that.
We could then switch again to attack d5: 28 Na3 intending 29 Nb5 and 30 Bb4 pinning the N/e7 against the R/f8. Then repositioning with 31 Ba3 and 32 Nc3 gets us to where we can take out the N defender and capture the d5 pawn on successive moves. But that leaves out Black's 28, 29, 30, 31 and 32, which undoubtedly could be used not only to adequately defend d5, but also do other mischief.
So 23 Bxd5 looks like a dead-end unless one of you see something better.

[B]23 Ne3[/B] allows instant neutralization: [B]23 ... Nxe3 24 Bxe3[/B], but that would also revive our old threat on c6: 25 Nxb7 Rxb7 26 Bxc6+. So, Black would have to double-defend b7 with [B]24 ... Nd8[/B]. Now c4 is undefended, but we don't have time for 25 Rf2 and 26 Bf1 because of 25 ... Bxg2. So, we have to do [B]25 Nxb7[/B] first. [B]25 ... Nxb7[/B] (not ... Rxb7) [B]26 Rf2 Nd8 27 Bf1 Rc8[/B]
Now [B]28 Bd2[/B] would revive our attack on Black's a&b pawns.

Black could defend a5 with 28 ... Nb7 but that wouldn't help b4: 29 cxb4 axb4 30 Bxb4. So, Black does [B]28 ... bxc3[/B] first. [B]29 Bxc3 Nb7[/B] and Black has defended both pawns from our bishops' attacks.

30 Rc1 would threaten to capture on c4 (or c3) after 31 Bd2. Black could delay that with 30 ... f6 threatening fxe5 and bxe5. 31 exf6 Bxf6 unleashes that bishop, so better would be to just defend e5. 31 Re2 would block our light-squared bishops' attack. So, we need to move a different rook on move 30.

[b]30 Rc2[/b], then if 30 ... f6 31 Re1 fxe5 32 dxe5, it's possible to continue Black's attack on e5 with 32 ... Rf5 but 33 g4 Rg5 34 h3 Rc5 35 Bd4 stops that (if 35 ... Bxe5 36 Bxc5 Nxc5 37 Bxc4).

What else might Black try on move 30?

There may be some way for Black to deviate from the bolded line above, but I hope all our bolded moves are so forcing that they leave Black no spare time.

- - -

Given my past record about seeing moves in this game, the chances of the game's playing out just as I've outlined are probably nil. :-(

Last fiddled with by cheesehead on 2014-02-24 at 00:57
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