Turn 11 for Black. I played Nd4 looking to protect my g7 bishop and stake a claim on their side of the board in the center. This was a mistake.
lichess.org/embed/Fl6LQRLp#24?theme=auto&bg=autoBelow is the FEN:
r1b2rk1/pp2ppbp/2nq2p1/2p5/2P5/2BP1N2/PP2BPPP/R2Q1RK1 b - - 2 11
I was playing black here after white moved Bd2 to Bc3, attacking my g7 Bishop (though defended by the King on g8). Why does stockfish suggest a move ignoring this, like b6, allowing the trade of the dark squared bishops and bringing the King to an open diagonal? It seems to be really against my intuitions. I thought in this kind of position that Black's dark squared bishop is preferred.
And further, why does Stockfish evaluate to -1? I can not see how Black is so advantaged, even after the trade.
11...Nd4 is playable, you get a big pawn centre. It's not the best move because it blocks your fianchetto bishop. The bad move was 14...b6 allowing the skewer. This fianchetto bishop is of course valuable but if you exchange it for opponent's bishop nothing happens, especially against maia1.
Yeah the skewer was definite obvious blunder, I was moreso curious about why Stockfish thought the position around move 11 was so good for black, and why it was so happy to lose the fianchetto bishop and bring the King to g7. Seems like a very counterintuitive way of playing. Is it just one of those computer lines I'm better off ignoring?
Problably stokfish gives a good advantage for black because the d3 pawn is weak, after your move that weakness disappears (because after the exchange the column is no longer open).
The probably with Nd4 is that the exchange helps black as white's d3 pawn won't be so vulnerable.
Concretely: 11...Bxc3 12.bxc3 Bf5 (or Rd8 first) followed by Rd8 and probably e5 looks excellent for black. The d pawn is weak and white's light squared bishop is passive.
By exchanging your g7 bishop you are creating slight weaknesses around your king, but white isn't really able to start an attack here. I don't agree with pointlesswindow's point that as long as you exchange it for your opponents bishop nothing bad happens, though white would ideally like to keep his DSB as well he's still usually happy to exchange them off because of the weaknesses he creates around your king. The problem is that your fianchettoed bishop keeps other pieces off of the f6 and h6 squares weakened by playing g7-g6 (imagine the mating patterns with a queen on h6 for example). This is why white usually plays Be3-h6 in the dragon or in the Pirc for example.
The computer wants you to play Kg8-g7 to cover these weaknesses.
With this being said, this is mostly positional stuff and since you blundered the exchange a move later that would be much more important to focus on.
#1
"why does Stockfish evaluate to -1? I can not see how Black is so advantaged, even after the trade."
Black has two advantages.
1) pawn d3 is a backward pawn on an open file and thus weak.
2) After the trade Bg7-Bc3, white has a bad bishop on the color of its own pawns and black has a good bishop,not on the color of its own pawns
"Why does stockfish suggest a move ignoring this, like b6, allowing the trade of the dark squared bishops and bringing the King to an open diagonal?"
The king is safe on g7. After the trade of the dark squared bishops black is left with a good bishop, active at b7, while white is left with a bad bishop, passive at e2.
Thank you so much everyone. The positional blunders and concepts I find much more difficult to understand from basic computer analysis compared to just tactics, which is why I asked about this specific move. Your explanations have clarified a lot and helped me think about these positions better.
