(1) W31 - B31
Analyzed Games ChessDoctor.com

00031.5.16 Analyzed by National Master Corey Russell

1.d4 d5 2.Nc3 e6 3.e4 dxe4 4.Nxe4 f5
This is a mistake. This weakens black's king (the e8-h5 diagonal is now open), doesn't develop, and not black is unable to boot a white piece from e5. He will have to use pieces now to do that. Instead, simple development like ...Nf6 or ...Bd7 followed by ...Bc6 is to be recommended.

5.Bg5
I understand your wish to post a knight on c5, but this move is dubious. By far, the e5 square is a better outpost. It is a hole in your opponent's position. A hole is a square that your opponent's pawns can't cover. c5, on the other hand, can easily be covered by the black b-pawn. Instead of Bg5, I recommend the following setup to take advantage of black's weakening by f5: Nc3, Bc4, Nf3, castles short (O-O), and Re1, with a definite advantage to white because b lack's e6 pawn is a target.

5...Be7 6.Bxe7 Qxe7 7.Nc5
I recommend 7. Nc3 instead

7...Nc6 8.d5
A good rule of thumb to follow is: don't attack until you've gotten all your knights & bishops out, and you've castled to safety! Your entire army wants to get involved in the fight. If you use just a few pieces, you can be overwhelmed if you opponent uses all of his pieces, kind of like a 3 on 1 fast break in basketball. Instead, Be2 looks best, so that if black tries to push ...e5, white won't have to worry about a discovered check, because the bishop would be blocking. After the text, black could win a pawn by playing 8. ... Qxc5 9. dxc6 Qxc6.

8...exd5+ 9.Ne2
This isn't good. Black is threatening ...Qxc5. White MUST prevent the loss of a piece. Qe2! does the job! Black can't take the knight since that would expose his king to check by the white queen on e2, which is illegal. White only loses a pawn this way. Also, the knight on e2 block's white's bishop from getting out. This will cause problems later. White's king-knight should be posted on f3 instead, where it helps to control the center.

9...f4 10.Qd2
This still hangs a piece on c5. Nb3, followed by 11. Qd2 (trying to castle-queenside and thereby free white's e2 knight to move) is the best way to proceed. 10. Qxd5 is possible, but black can get a lot of tempo (extra moves) on white, so it's probably not worth it. For example, 10. Qxd5 Nf6 11. Qc4 O-O-O, and now white can't even castle

10...Ne5 11.Nxf4
This should lose, as now black can now win white's queen by force. Do you see it? Instead, preserving white's c5 piece with Nb3 is much preferable.

11...Nc4+
Oops! Wrong check! Much better for black is 11. ... Nf3+ 12. Kd1 (forced, since it's double-check) Nxd2 13. Kxd2 Qxc5, with a crushing position for black.

12.Be2
Uh, oh, white returns the favor. White's queen is in jeapordy, and his king is in check. Is there any move that will get the queen out of danger, AND block the check? Yes! Qe2! Not only that, it even indirectly defends white's knight at c5, since the black queen is pinned to her king. Instead, black procures a large amount of material.

12...Nxd2 13.Kxd2 g5 14.Nce6
This should lose immediately after 14. ... gxf4. Notice if 15. Bh5+ Kd7 16. Bg4 Kd6, and black's king is perfeclty safe.

14...Qb4+ 15.Kc1 Qxf4+
Black commits a minor blunder. He's still winning, but white can take black's queen with 16. Nxf4 gxf4. This would leave black with a piece up, though his development is severely lagging. This is still far better than what actually happened for white.

16.Kb1 Qxf2 17.Rf1 Qxg2
There was no reason for black not to dominate the white bishop.

18.Bb5+ c6 19.Nc7+ Ke7 20.Re1+ Kf6 21.Ne8+ Kf7 22.Nd6+ Kf6 23.h3
Why not continue checking with Ne8+? Maybe black will repeat the position 3 times with the same person to move, and then you can legally claim a draw!

23...Bxh3 24.Nxb7
White's bishop is hanging. Instead, preserving the bishop with say Bd3 is superior (though black's still winning).

24...Re8 25.Rxe8
This ignore's black's threat of back rank mate. Instead Rc1 would fight on (sort of). Black's advantage would stil be huge.

25...Qg1+ 26.Bf1 Qxf1+ 27.Re1 Qxe1# *