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Philidor IV

Posted: Sat Apr 08, 2017 4:36 pm
by Henk
What should black play against this gambit ? Don't tell me he has to exchange it's queen against a rook, bishop and a pawn.

[d] r1bqkb1r/pppn1ppp/3p1n2/4p3/3PP1P1/2N2N2/PPP2P1P/R1BQKB1R b KQkq g3 0 5

Re: Philidor IV

Posted: Wed Apr 12, 2017 3:51 pm
by Henk
Are there no black lion players here? I thought safest move is h6. But I already forgot why.

Re: Philidor IV

Posted: Thu Apr 13, 2017 3:37 am
by gerold
Henk wrote:What should black play against this gambit ? Don't tell me he has to exchange it's queen against a rook, bishop and a pawn.

[d] r1bqkb1r/pppn1ppp/3p1n2/4p3/3PP1P1/2N2N2/PPP2P1P/R1BQKB1R b KQkq g3 0 5
Nxg4

Best,
Gerold.

Re: Philidor IV

Posted: Sat May 27, 2017 12:33 pm
by Lyudmil Tsvetkov
Henk wrote:What should black play against this gambit ? Don't tell me he has to exchange it's queen against a rook, bishop and a pawn.

[d] r1bqkb1r/pppn1ppp/3p1n2/4p3/3PP1P1/2N2N2/PPP2P1P/R1BQKB1R b KQkq g3 0 5
all gambits are to be accepted.

of course, as Gerold suggests, Ng4. I do not see any compensation for the pawn.

is this the latest swing of the Van den Belt Gambit?

Re: Philidor IV

Posted: Sat May 27, 2017 4:02 pm
by Henk
Lyudmil Tsvetkov wrote:
Henk wrote:What should black play against this gambit ? Don't tell me he has to exchange it's queen against a rook, bishop and a pawn.

[d] r1bqkb1r/pppn1ppp/3p1n2/4p3/3PP1P1/2N2N2/PPP2P1P/R1BQKB1R b KQkq g3 0 5
all gambits are to be accepted.

of course, as Gerold suggests, Ng4. I do not see any compensation for the pawn.

is this the latest swing of the Van den Belt Gambit?
No it is called Shirov-Philidor gambit. Too violent for me. But what can you do about it for I play with black.

[pgn]
[Event "?"]
[Site "?"]
[Date "?"]
[Round "-"]
[White "?"]
[Black "?"]
[Result "*"]
[FEN "r1bqkb1r/pppn1ppp/3p1n2/4p3/3PP1P1/2N2N2/PPP2P1P/R1BQKB1R b KQkq g3 0 1"]
1... Nxg4 2. Rg1 Ngf6 3. Bc4 h6 4. dxe5 dxe5 5. Qd3 c6 6. Be3 b5 7. Bxf7+
Kxf7 8. Nxe5+ Nxe5 9. Qxd8 Nf3+ 10. Kd1 Nxg1 11. Kc1
*
[/pgn]

Re: Philidor IV

Posted: Sat May 27, 2017 9:01 pm
by Ras
Lyudmil Tsvetkov wrote:of course, as Gerold suggests, Ng4. I do not see any compensation for the pawn.
I do - the open g file and the rook on said file. Probably, that isn't enough compensation, but at least some. The main issue for Black is that castling kingside is out of question, and castling queenside takes more time.

DeepShredder 13 evaluates the position after 5. ... Nxg4 with -0.38 in favour of Black, and after 5. ... h6 with +0.15 in favour of White, both at depth 33. That's a difference of 0.53 pawns. So the compensation is worth 0.47 pawns, according to DeepShredder.

Re: Philidor IV

Posted: Sun May 28, 2017 11:44 am
by Sean Evans
Black needed to develop more pieces, white was dominating with development.

Re: Philidor IV

Posted: Sun May 28, 2017 2:53 pm
by Lyudmil Tsvetkov
Ras wrote:
Lyudmil Tsvetkov wrote:of course, as Gerold suggests, Ng4. I do not see any compensation for the pawn.
I do - the open g file and the rook on said file. Probably, that isn't enough compensation, but at least some. The main issue for Black is that castling kingside is out of question, and castling queenside takes more time.

DeepShredder 13 evaluates the position after 5. ... Nxg4 with -0.38 in favour of Black, and after 5. ... h6 with +0.15 in favour of White, both at depth 33. That's a difference of 0.53 pawns. So the compensation is worth 0.47 pawns, according to DeepShredder.
g is a semi-open, and not an open file.

also, if black has 40cps edge after the knight capture, there is certainly no compensation.

I guess Shredder assesses both lines accurately here.

if I have to go further, I guess Ng4 simply wins the game, but that is not easy to prove.

Re: Philidor IV

Posted: Sun May 28, 2017 7:09 pm
by Ras
Lyudmil Tsvetkov wrote:also, if black has 40cps edge after the knight capture, there is certainly no compensation.
If there were no compensation at all, I would expect black to have an edge of 100cps, the material value of the pawn.

I've been digging a bit deeper through the variants to include this gambit as passive knowledge in the CT800's book. The issue is that Black has the better endgame if nothing changes, but reaching that is not easy.

Black cannot castle kingside, and in most variants, not queenside, either. This in turn seriously hampers the rooks' mobility. In fact, with absolutely correct play, Black has the edge, but it is quite a narrow path from having the edge to losing the game.

Looks like a good gambit especially for blitz games, or for tournament sitations where White must make the full point at all cost.

Re: Philidor IV

Posted: Sun May 28, 2017 7:59 pm
by Henk
[pgn]
[Event "Bundesliga 2008/09"]
[Site "Various GER"]
[Date "2008.10.04"]
[EventDate "2008.??.??"]
[Round "1.1"]
[Result "1-0"]
[White "Alexey Shirov"]
[Black "Lukasz Cyborowski"]
[ECO "C41"]
[WhiteElo "2741"]
[BlackElo "2546"]
[PlyCount "45"]

1. e4 d6 2. d4 Nf6 3. Nc3 e5 4. Nf3 Nbd7 5. g4 Nxg4 6. Rg1
Ngf6 7. Bc4 h6 8. Be3 Nb6 9. Bb3 exd4 10. Qxd4 Bg4 11. Rg3 c5
12. Qd3 Rc8 13. e5 dxe5 14. Nxe5 Bh5 15. Qf5 Bd6 16. Ne4 Qe7
17. Nxd6+ Qxd6 18. Rxg7 Rc7 19. Bxf7+ Bxf7 20. Rd1 Nbd5
21. Nxf7 Qxh2 22. Nxh8 Rxg7 23. Qc8+ 1-0
[/pgn]