This came about via 1.e4 Nf6 2.Nc3 d5 3.e5 Nfd7 4.d4 c5 5.Nf3 e6.
However here I want to look at what happens if White sacrifices a pawn at move four by playing 4.e6!?, which dates back to at least 1930.
Black is more-or-less obliged to reply 4...fxe6, after which the black position is clearly compromised, but is that enough compensation?
 |
| Position after 4...fxe6 |
What makes these evaluations particularly interesting is that often it is Komodo12.1.1 which gives more value to positional matters while Stockfish14.1 is often more coldly materialistic.
In this case, giving the engines more time sees the evaluations converging somewhat, although still with Stockfish14.1 favouring White and Komodo12.1.1 favouring Black.
The first thing to note is that the continuation 5.Qh5+? is not only easily met by 5...g6 but actually helps Black prepare a development square for the black king's bishop.
Similarly 5.Bd3?!, hoping for something like 5...c5?? 6.Qh5+ g6 7.Qxg6+ hxg6 8.Bxg6#, is wildly optimistic.
So it is hardly surprising that 354 out of 366 games in ChessBase's 2022 Mega database see 5.d4.
Black already has to be a little careful, eg the plausible 5...e5? 6.dxe5 Nxe5? 7.Qxd5 was played in Rauno Järvinen (2119) - Vitālijs Samoļins (2426), Tartu (Estonia) Rapid Under-26 2010, after which 7...Nf7 8.Be3 e6 9.Qxd8+ Nxd8 10.Nf3 left White well on top (1-0, 41 moves).
Three moves in reply to 5.d4 have been tried by grandmasters and appear frequently enough in Mega22 to deserve serious consideration.
A) 5...Nf6 (54 games) returns the king's knight to its normal development square and covers h5.
After 6.Nf3 it is clear Black is likely to have to fianchetto the black king's bishop at some point, which is why Black's commonest response is the sensible-looking 6...g6, when Liviu-Dieter Nisipeanu (2515) - Csaba Horváth (2540), Balatonberény (Hungary) 1996, continued 7.h4!? Bg7 8.Bd3 c5 9.dxc5 Nc6 10.h5!? gxh5 11.Bf4 Qa5 12.Qd2 Bd7 13.0-0-0 0-0 with an unclear position that, according to the engines, quickly saw several mistakes before a draw was somewhat prematurely agreed at move 17.
B) 5...g6 (70 games) is another way to quickly develop the king's bishop while protecting the h5 square.
After 6.h4!? the most-popular reply in Mega22 is 6...Nf6?!, but this is probably a mistake as White has 7.h5!, when Juan Manuel Bellón López (2324) - Vlatko Kovačević (2454), Karlovac (Yugoslavia) 1979, continued 7...Nxh5 8.Rxh5 gxh5 9.Qxh5+ Kd7, when 10.Nxd5! would have given White a large advantage, eg 10...exd5 11.Qxd5+ Ke8 12.Qh5+ Kd7 13.Nf3, after which White is down rook for pawn but is crushingly winning, according to the engines, best-play apparently running 13...c6 14.Bf4 Bg7!? 15.Qg4+ Ke8 16.Qxg7 Rf8 17.Bg5 with obvious compensation.
The engines prefer capturing on h5 with the pawn, ie 7...gxh5, but reckon 8.Be2 Bg7 9.Bxh5+, as in Maximiliano Preuss (2114) - Aldo Emilio Seidler (2330), Benko Memorial (Buenos Aries) 2010, is good for White.
That game continued 9...Kf8 10.Nf3 Nxh5!? (the engines prefer 10...c5) 11.Rxh5 Nd7 12.Bh6 with a strong attack (1-0, 23 moves).
C) 5...c5 (212 games) is easily most-popular and probably best.
The reply 6.Bd3?! looks overly optimistic in view of 6...g6, when 7.h4? cxd4 must be good for Black, so White should probably choose between 6.dxc5 and 6.Nf3.
C1) After 6.dxc5 Nc6 7.Nf3 g6 the engines like the slightly unusual 8.Nd4!?, when the commonest reply, 8...Nf6, can be met by 9.Bb5, with the engines continuing 9...Qc7 10.0-0 Bg7 11.Re1!? (this would seem to be a potential novelty), claiming a sizeable advantage for White.
The engines reckon a better try for Black is 8...Nde5!?, when 9.f4 Nf7 10.Bb5 Bd7 (better than 10...Qc7, according to the engines) 11.Be3 Bg7 12.Qd2 0-0 13.0-0-0 is given as equal, but looks very unclear to me and may well be easier for White to play.
C2) 6.Nf3 is the main move in Mega22, after which Black usually replies 6...Nc6, when 7.dxc5 transposes to C1.
However the engines very slightly prefer 6...g6, when 7.h4 Bg7 8.h5 can be calmly met by 8...Nc6.
The engines suggest what would be an apparent novelty in 7.dxc5!?. If then 7...Bg7, which they reckon is best, they come to like 8.h4, after which the line splits.
C2a) 8...Nf6 9.h5!? Nxh5 is unclear, with 10.Rxh5, 10.Bd3 and 10.Ng5 all seeming promising for White. Also unclear is 9...gxh5, eg 10.Bb5+ Bd7 11.Qe2 a6 12.Bxd7+ Nbxd7 13.Be3, when White has more than enough compensation for a pawn, according to the engines.
C2b) 8...Nc6 is preferred by the engines, when they reckon it is worth spending a tempo on protecting the c5 pawn with 9.Be3!? rather than immediately pushing on with the h pawn. Again the position is unclear, but may slightly favour Black after Komodo12.1.1's 9...Qa5!?
In the light of this White may be well-advised to try the less-popular 6.dxc5, ie C1. Several black moves in the main continuations are hard to find and it is easy for the second player to go wrong, eg 6...Nxc5?! is plausible, when all five games in Mega22 continue 7.Nf3 Nc6 8.Bb5, with Stockfish14 claiming White has at least the upper hand and is possibly positionally winning. Komodo12.1.1 is less enthusiastic about White's chances, but the Black kingside does look vulnerable.
CONCLUSION: The pawn-sac 4.e6!? gives White a promising game and could come as a nasty surprise for opponents, especially as in several lines Black has to be careful to avoid intuitive moves that give White the upper hand.
No comments:
Post a Comment