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Subject: Re: Just wondering...

Author: John Merlino

Date: 12:45:27 05/27/05

Go up one level in this thread


On May 27, 2005 at 14:11:52, Jack Lad wrote:

>1.e4 e5 2.Nf3 d6 3.d4 exd4 4.Qxd4 Nc6 5.Qd5 Bd7 6.Bc4 Qe7 7.Bg5 Nf6
>8.Bxf6 Qxf6 9.Nc3 Be7 10.O-O O-O 11.Qd3 Nb4 12.Qd2 Bh3 13.Ne1 Bg4 14.f3
>Bd7 15.f4 d5 16.Bxd5 Bc5+ 17.Kh1 Rad8 18.Nf3 Qb6 19.a3 Nxd5 20.Nxd5 Qe6
>21.b4 Bb6 22.f5 Qxe4
>[d]3r1rk1/pppb1ppp/1b6/3N1P2/1P2q3/P4N2/2PQ2PP/R4R1K w - - 0 23
>
>Does 23.f6 force the loss of black's queen?
>For example:
>
>23.f6 h6 24.fxg7 Kxg7 25.Rae1 Qc4 26.Nxb6 cxb6 27.Ne5 Qe6 28.Qc3 Kh7 29.Nxf7
>Rxf7 30.Qd3+ Kg7 31.Rxe6 1-0
>
>or
>
>23.f6 Bf5 24.Qg5 Bg6 25.Ne7+ Kh8 26.Ne5 Rd6 27.Rfe1 Qxe1+ (or ...Rxf6 28.Rxe4)
>28.Rxe1 1-0

Indeed, your first line appears to put White ahead by a Queen and Pawn vs Rook
and Bishop, which should convert into a win with little difficulty. A brief
search of the final position shows an eval of about +4.0.

However, from the initial position, I suspect that many engines might prefer
23.Rae1. CM9_R1 gives that move a +3.55 eval after just over a minute and a
half:

Time	Depth	Score	Positions	Moves
0:00	1/3	0.23	1153		23.Rae1 Qc4 24.Ne5
0:00	1/4	0.48	2785		23.Rae1 Qc4 24.Ne5 Qd4
0:00	1/4	0.54	3885		23.Rfe1 Qc4 24.Nxb6 axb6 25.Rad1
0:00	1/4	1.42	16163		23.f6 Rfe8 24.fxg7 Qe6 25.Qg5
0:00	1/5	1.72	36601		23.f6 Rfe8 24.Qg5 Qg4 25.Ne7+ Rxe7
					26.Qxg4 Bxg4 27.fxe7
0:00	1/6	2.21	159983		23.f6 Bf5 24.fxg7 Qxd5 25.Qxd5
					Rxd5 26.gxf8=Q+ Kxf8 27.c4 Rd8
					28.c5
0:01	1/7	1.64	372951		23.f6 Be3 24.Nxe3 Bb5 25.Qf2 Bxf1
					26.fxg7 Bxg2+ 27.Qxg2 Rfe8
0:03	1/8	2.08	929362		23.f6 Bf5 24.fxg7 Kxg7 25.Qg5+
					Bg6 26.Qf6+ Kh6 27.Nxb6 cxb6 28.Rae1
					Qxc2 29.Ne5
0:09	1/9	1.99	2410686		23.f6 Bf5 24.Ne7+ Kh8 25.Qg5 Bg6
					26.Ne5 Rd6 27.fxg7+ Kxg7 28.Nf5+
					Kg8 29.Nxd6 cxd6 30.Nd7 Be3
0:10	1/9	2.15	2732018		23.Rfe1 Qg4 24.Ne5 Qh4 25.Nxb6
					Bxf5 26.Nd5 c6 27.Nf3 Rxd5 28.Nxh4
					Rxd2 29.Nxf5 Rxc2
0:13	1/10	2.55	3837649		23.Rfe1 Qg4 24.Ne7+ Kh8 25.Ne5
					Qd4 26.Rad1 Be6 27.Qe2 Qh4 28.fxe6
					Rxd1 29.Rxd1 Qxe7 30.exf7 Rxf7
					31.Nxf7+ Qxf7
0:32	1/10	2.82	8883316		23.Rae1 Qg4 24.Ne5 Qd4 25.Ne7+
					Kh8 26.Qg5 h6 27.Nxf7+ Rxf7 28.Ng6+
					Kh7 29.Qxd8 Bxf5
0:45	1/11	2.75	13088121	23.Rae1 Qg4 24.Ne5 Qh4 25.f6 Be6
					26.Ne7+ Kh8 27.Qxd8 Rxd8 28.Nxf7+
					Bxf7 29.fxg7+ Kxg7 30.Nf5+ Kf8
					31.Nxh4 Rd2 32.c4 Bd4
1:26	1/12	3.55	26057973	23.Rae1 Qg4 24.Ne7+ Kh8 25.Ne5
					Qd4 26.Qg5 h6 27.Qh5 Kh7 28.Nxf7
					Rxf7 29.Qxf7 Qg4 30.Qg6+ Qxg6 31.fxg6+
					Kh8 32.Nf5

And after forcing 23.Rae1 Qg4 24.Ne7+ Kh8 25.Ne5 the eval is also over +4 in a
similar amount of time:

Time	Depth	Score	Positions	Moves
0:00	1/3	-0.20	2365		25...Qd4 26.Qd3 Qxd3 27.cxd3
0:00	1/4	-0.46	5347		25...Qd4 26.Qxd4 Bxd4 27.f6 Be6
					28.Nf5
0:00	1/5	-0.02	21208		25...Qd4 26.Qe2 Qd6 27.f6 gxf6
0:00	1/6	-0.08	53287		25...Qd4 26.Qe2 Qd6 27.f6 gxf6
					28.Nxd7 Rxd7
0:00	1/7	2.67	141313		25...Qd4 26.Qg5 h6 27.Nxf7+ Rxf7
					28.Ng6+ Kh7 29.Qxd8 Bxf5
0:00	1/8	2.35	268547		25...Qd4 26.Qg5 h6 27.Nxf7+ Rxf7
					28.Ng6+ Kh7 29.Qxd8 Bxf5 30.Nf8+
					Kg8 31.Nd7+ Kh7 32.Qe8 Qxd7 33.Qxd7
					Rxd7 34.Rxf5
0:02	1/9	2.35	626799		25...Qd4 26.Qg5 h6 27.Nxf7+ Rxf7
					28.Ng6+ Kh7 29.Qxd8 Bxf5 30.Nf8+
					Kg8 31.Nd7+ Kh7 32.Qe8 Qxd7 33.Qxd7
					Rxd7 34.Rxf5
0:06	1/10	3.59	1957430		25...Qd4 26.Qg5 h6 27.Qh5 Kh7 28.Nxf7
					Rxf7 29.Qg6+ Kh8 30.Qxf7 Qf6 31.Ng6+
					Kh7 32.Nf8+ Rxf8 33.Qxd7
0:17	1/11	3.78	5364792		25...Qd4 26.Qg5 h6 27.Qh5 Qd6 28.Qxf7
					Rxf7 29.Nxf7+ Kh7 30.Nxd6 cxd6
					31.Nd5 Bd4 32.Re7 Bb5 33.Rd1
0:38	1/12	3.83	12354397	25...Qd4 26.Qg5 h6 27.Qh5 Qd6 28.f6
					Be6 29.N5g6+ Kh7 30.Nxf8+ Rxf8
					31.fxg7 Kxg7 32.Nf5+ Bxf5 33.Qxf5
					Qg6 34.Re7 Qxf5 35.Rxf5
1:37	1/13	4.07	31654205	25...Qd4 26.Qg5 h6 27.Qh5 Qd6 28.Nxf7+
					Rxf7 29.Qxf7 Bd4 30.Rd1 Qf6 31.Ng6+
					Kh7 32.Qxf6 Bxf6 33.Nf8+ Rxf8 34.Rxd7

jm



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