TN wrote on 02/27/11 at 13:21:36:
sloughter wrote on 02/27/11 at 10:00:03:
Jonathan Tait wrote on 02/26/11 at 18:01:21:
sloughter wrote on 02/26/11 at 11:23:49:
You have to treat 6...Qf8 a little differently from 6...Rf8 i.e. 7.O-O! d6 8.d3 Bg4 9.Nf3 Nd4 10.Nbd2 Nh5 11.c3 Nxf3ch 12.Nxf3 Qf6 13.Bg5! Qxg5 14.Nxg5 Bxd1 15.Raxd1 +-
12...Qf6 is a mistake. Black should take on f3 and then clamp down on the f4-square. White's extra pawn doesn't have much significance with the doubled f-pawns fixed and backwards.
Agreed, but White can improve:
8.Nc3! Bg4 9.Nd5ch! Kd8 10.Nxf6! Bxd1 11.Ne6ch +-
Remind me sloughter, what was your 'refutation' of 4...d5 5.ed5 Na5 6.Bb5 c6 7.dc6 bc6?
There is 'theoretical' refutation and there is practical refutation. A theoretical refutation is one where any advantage, no matter how small, with best play can be converted into a win even if it takes a 1000 moves of best play by both sides. A refutation by a Class D player may be finding checkmate in one move. All other practical wins lie in the middle.
A good illustration of a refutation of a Queen and pawn versus Queen ending is when I think it was IM Jerermy Silman (?) was a pawn up in a Queen and pawn versus Queen ending. The computer claimed that he had a checkmate in 83 moves. Silman made a move and the computer promptly claimed checkmate in 87 moves. Thus a theoretical win for a computer in a Queen and pawn ending is always favorable to a computer over a human and what constitutes a refutation depends entirely on whether you are referring to a computer refutation or a human refutation.
When you hear the phrase that White is on the better side of the draw, this has no meaning in a theoretical sense, but does so in a practical sense.
I think in the future that it will be generally regarded that White has a slight theoretical plus in the TKD (The first move advantage) but that the wins will take over 100 moves to prove in many examples. For example to prove a win in the line 5...Na5 6.Bb5ch Bd7, the line that it will take an extremely long time to win, White will win the heavy piece ending (the minors will oppose one another and they will eventually all be chopped off), but then White has to try to demonstrate in a heavy piece ending that the extra pawn matters.
The winnning procedure will consist of pushing the Queenside pawns slowly, rearranging the majors, eventually creating a passed pawn and then create a target on the Kingside. Then using threats on both sides of the board White will be able maybe 60-80 moves ahead to Queen a pawn.
The extra pawn is a theoretical win in this opening but an incredibly difficult win for a human player in the heavy piece ending but a simple practical win for a World Class computer.
In other words, you don't have a refutation for 5...Na5.