5
[fen "r3k1nr/pppqn2p/5p2/b5p1/3PP3/1BP2QBP/PP1N2P1/R3K2R w KQkq - 3 14"]

This game was played by me on chess.com recently. (I am white). The material balance is +1 (for white). Then why is Stockfish evaluating such huge advantage for white? (White to move)

My complete game (just in case):

[fen ""]
1. e4 e5 2. f4 exf4 3. d4 Bb4+ 4. c3 Ba5 5. Bxf4 d6 6. Nf3 f6 7. Bc4 g5 8. Bg3 Nc6 9. Nbd2 d5 10. Bxd5 Bg4 11. h3 Bxf3 12. Qxf3 Nce7 13. Bb3 Qd7 14. O-O O-O-O 15. Nc4 b6 16. Nxa5 bxa5 17. e5 fxe5 18. Qa8# 1-0

The given position is after move 13.

3
  • 3
    I put this position on Stockfish and found really interesting that it gives a huge advantage from ply 1. Since there's no immediate material imbalance, that probably means that there's something really wrong with black position. I used the static evaluation of Stockfish and it seems the very big issue of black's position is its King's safety.
    – emdio
    Oct 1 at 18:06
  • 1
    I don't know what kind of answer you are looking for, but I will say that Stockfish (and engines as a whole) are way past the point of just counting the material on the board. They take into account king safety, mobility, pawn structure, and a lot of other factors. It should not be so surprising that a position with +1 material can nonetheless yield a +7 eval for one side, since all the positional factors here are in White's favor.
    – Allure
    Oct 3 at 12:28
  • @emdio: It's extremely misleading to do a static analysis on the initial position. In the first place, the evaluation is the result of a pruned alpha-beta search, so the final score is the static evaluation of some position many plies later. It turns out that in fact the high evaluation is partly due to a huge material loss later, as I explained in my answer.
    – user21820
    Oct 5 at 21:00
4

It's hard to explain why Stockfish goes for such a big advantage to White despite the fact of there being no direct winning continuation (according to Stockfish, White has several different moves and plans that keep the advantage). Anyway it doesn't matter much whether the position is +3, +5, +7 or forced mate in 23. A human can figure out that this position must be winning for reasons like:

  • White is one pawn up, so even if a potential attack doesn't work there's still good chances to win in the endgame.

  • White has more active pieces and, perhaps more importantly, better ways to activate the pieces that are still passive. Compare the knights on d2 and g8 or the rooks on h1 and h8 for instance.

  • Black has several weaknesses on the light squares. The defense of the f6 pawn is not an easy problem to solve.

  • Black's king has no hope to find a safe square to go. Castling kingside is almost out of the question due to all the weak light squares on that side of the board. Staying on the center means Black has to worry about Qh5+ threats in almost eveyr move. Castling queenside is bad because White can easily start an attack by chasing the enemy bishop. For instance, after 0-0 0-0-0, White can play Nc4 followed by a4 and a5 (as you saw in your game, the bishop must retreat because ...b6 leaves the Black king hopeless)

3

I'm a beginner so take everything I say with a grain of salt. Here is what I see. The difference in quality of the pieces does really stand out.

White

  • wide open bishops on the long diagonals
  • dominant center control with solid pawn structure
  • good prospects for the knight
  • can easily castle and create an attack by pushing the already advanced pawns

Black

  • bishop is stuck staring at pawns, no obvious way of improving its position
  • knights are stuck, pawns control most of the squares they could reposition to
  • h8 rook is stuck behind a knight that can barely move (Nh6 is a move, but really ugly, and from there the knight can only go back to g8)
  • light squares are weak (pawns on dark squares) and no light squared bishop to control them

I wrote the following two points looking by mistake at the position a ply earlier, with black to move when the queen was on d8:

  • queen only has 3 forward squares to move to, 2 of them controlled by white's excellent bishops
  • to be able to castle either the knight or the queen have to make the only move they can reasonably make, and neither looks good

It just looks to me like black tied their shoes together, AND is a pawn down.

2

The main approach seems to be:

[FEN "r3k1nr/pppqn2p/5p2/b5p1/3PP3/1BP2QBP/PP1N2P1/R3K2R w KQkq - 3 14"]

1. Nc4 Bb6 2. Ne5 fxe5 (2... Qd6 3. Nf7 Qc6 4. O-O f5 5. Nxh8 O-O-O 6. Nf7 Rf8 7. Nxg5 Nf6 8. Rae1 a5 9. exf5 Qxf3 10. Rxf3) 3. Bf7+ Kd8 4. Bxe5 Nh6 5. Bxh8 Nxf7 6. Qxf7 Qe8 7. Qxh7

At the end, White has the following major advantages:

  1. Up a rook and 3 pawns for a knight. Roughly +5.
  2. A candidate passed pawn (e4) in a connected pair.
  3. Black king cannot castle and is stuck in the middle (high king-danger).

The second factor can often be used to force the opponent to sacrifice a minor piece, which would result in a material advantage of a rook plus 2 pawns even ignoring all other advantages. In fact, the pawn at g5 is kind of dead, and so after a few more moves Stockfish sees the outcome as more or less like:

[FEN "r3k1nr/pppqn2p/5p2/b5p1/3PP3/1BP2QBP/PP1N2P1/R3K2R w KQkq - 3 14"]

1. Nc4 Bb6 2. Ne5 fxe5 3. Bf7+ Kd8 4. Bxe5 Nh6 5. Bxh8 Nxf7 6. Qxf7 Qe8 7. Qxh7 Qg6 8. Qxg6 Nxg6 9. O-O Ke8 10. Bf6 c5 11. d5 c4+ 12. Kh1 Bd8 13. Bxd8 Rxd8 14. Rf5 Rd6 15. Rxg5

The other main option for Black also leads to ruin:

[FEN "r3k1nr/pppqn2p/5p2/b5p1/3PP3/1BP2QBP/PP1N2P1/R3K2R w KQkq - 3 14"]

1. Nc4 Qb5 2. d5 O-O-O 3. O-O-O Kb8 4. d6 cxd6 5. Rxd6 Ka8 6. Rxd8+ Bxd8 7. Nd6 g4 (7... Qc6 8. Nf7 Bb6 9. Nxh8) 8. hxg4 Qg5+ 9. Kc2 Nh6 10. Bf4 Qxg4 11. Bxh6
0

My first impulse was to gain a tempo on the unprotected bishop on a with Nc5 and start rolling my a pawn down (tempo and space!), and my second thought was to push e5 and threaten to either fully pass a pawn or get a nice juicy check in on f7 -- I like a king that can't castle when the queens are still on the board...

I also considered bxg8 for Qh5+ but realized NexB allows Qf7 and exchanging leaves the black king on f7, in better position to play as a fighting piece now that the queens are off.

Summarizing to your question: this was a position that prompted aggression.

2
  • 1
    Yep! If at all Qh5+ should be done without trading the bishop
    – David
    Oct 2 at 13:23
  • 1
    After e5, also don't forget about a b7 target. Black has just too many problems to worry about.
    – user58697
    Oct 2 at 23:10

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