Thread: White 20
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Old 2014-02-06, 19:09   #9
cheesehead
 
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"Richard B. Woods"
Aug 2002
Wisconsin USA

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[QUOTE=LaurV;366294]< snip > [B]20.Nf2[/B]. < snip >
[B]20...Nd5[/B] < snip > [B]21.Nf2e4[/B], they can't take the bishop,[/QUOTE]Actually, they can. 21 ... Nxe3 22 Nd6+ Kd8 23 Rxf7 Nxg2 24 Rxg7 Ne3 and Black has captured both of our bishops in exchange for a bishop and pawn ...

... but we can pick off several more pawns. E.g., 25 Rxg6 Kd7 (preventing Rxe6) 26 Rg7+ Kd8 27 Re1 Nf5 28 Nxf5 exf5 29 Rg6 Bb7 (not ... Ne7 30 Rxa6 or ... Rf8 30 Rxc6) 30 Rf6 Ne7 31 Nxc4 (we finally get the third pawn in exchange for our bishop) Ra8 32 Nd6 Bc6 33 Nxf5 Bxa4 34 Nxh6 (getting our fourth pawn for the bishop) Bb3 (preventing 35 Nf7+ from winning a rook) 35 R1f1 (threat Rf8+) Re8 36 Rf8 Kd7 and we have four pawns for the bishop but it's still a struggle.

[quote]But still, after 21...castling, we may Nf6 (already discussed, but it was the other horse, what is different now??[/quote]Now, we don't have a defender for the e3 bishop (or c3 pawn). We do have connected rooks, however.

[quote]do we need to defend the bishop and need to lose moves retreating it, or we can ignore it and continue the attach?)[/quote][B]21 ... O-O 22 Nf6+ Bxf6[/B] (not ... Nxf6 23 exf6 Bh8 24 Bxh6) [B]23 exf6 Nxe3[/B].
If 24 Bxc6 Nxf1 25 Rxf1 bxc3 26 bxc3 Rb2 27 Ne4 R8b8, then Black can force a rook exchange, and then we lose.
If 24 Rf2 Nxg2 25 Kxg2 bxc3 26 bxc3 and ... whoops, we're down a whole bishop.

So I think we can't afford to allow ... Nxe3 without immediate re-take.

- - -

But we may have something better. Note what I said above about Black's having just enough time (none to spare) to meet our Rf2 and Bf1 threat. Can we interleave our two different threats, leaving Black unable to meet both?

I haven't figured it all out yet, but it starts with
[b]20 Rf2 Rc8[/b] (forced, else Black can't meet 21 Bf1)
[b]21 Bf1 Nb8[/b] (again, forced)
( But remember that ... bxc3, bxc3 can be interpolated any time here )
[b]22 Ne4 O-O 23 Nd6[/b] (this is where I deviate from previous analysis in post #7)
Now 23 ... Nd5 isn't feasible.
If 23 ... Rc6 or Rc7 24 Bd2 (threatening to attack c4 a third time with 25 Ne3. Here ... Nd5 has no threat to capture our bishop. Black can't add a third defender with Rfc8 yet.) Nc8 25 Nb5 Bxb5 26 axb5.
Now Black's only defense of a5 is 26 ... Ra7, but that allows us to capture the c4 pawn with 27 Bxc4. 27 ... Nb6 chases the bishop back, but too late to save the c-pawn.

Last fiddled with by cheesehead on 2014-02-06 at 19:57
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