Wednesday, December 28, 2016

The Zaitsev Variation of the Benko Gambit

1 d4 Nf6 2 c4 c5 3 d5 b5 4 cxb5 a6

I date back to the early days of the Benko Gambit in the early 1970's, so it is rather amazing to me that it has now grown in popularity to where it is now is the preferred choice of black players by 2-1 over 3...e6, reflecting the general consensus that the gambit has a strong positional basis.

5 Nc3

This initiates the Zeitsev Variation. Objectively it is not the best way for white to proceed, but its trappy play gives black many chances to go wrong. 5 Nc3 has only a 46% success rate, compared to 53% each for 4 bxa6 and 4 b6, 56% for 4...e3, and 54% for 4 f3.

5...axb5 6 e4 b4 7 Nb5 d6


The point of white's play is that 6...Nxe4 is out because of 7 Qe2 Nf6 8Nd6#. With 6...d6, black meets this threat and again threatens the P on e4.

8 Bf4

The main move, the alternative being 7 Bc4, after which the usual continuation is  8...Nbd7 9 Nf3 Nb6 10 Bd3 g6 11 b3 Bg7 12 Bb2 0-0 13 0-0 Ba6 14 Qe2 Qd7 15 a4 bxa3 16 Rxa3.

8...g5

Easily the strongest move, causing discomfort to the white B on f4. The advantage of this line for white is that a black player not familiar with this opening is unlikely to find this odd-looking move.

Surprisingly, 8...Nxe4 is actually playable. 9 Qe2 led to a draw after 9. Qe2 g5 10. Qxe4 gxf4 11. Nf3 Qb6 12. Nd2 f5 13. Nc4 fxe4 14. Nxb6 Ra5 15. Nxc8 Bg7 16. Bc4 Bxb2 17. Rb1 Be5 18. Nca7 Kf7 19. Kd2 Kf6 20. Kc2 Nd7 21. Nc6 Raa8 22. Rhe1 Nb6 23. Nxe5 Kxe5 24. Bd3 1/2-1/2


Stronger for white is 9 Bd3 (instead of 9 Qe2); one continuation runs  g5 10. Be3 Nf6 11. Bxg5 Bg7 12. Ne2 Nbd7 13. Ng3 Ne5 14. O-O Qb6 15. a4 bxa3 16. Rxa3 Rxa3 17. bxa3  O-O 18. a4 c4 19. Bc2 Bg4 20. Qd2 Qc5 21. Nc3 Nd3 22. Bxd3 cxd3 23. Qxd3 Qa3 24. Qd2 Rc8 25. Nce4 Nxe4 26. Nxe4 f6 27. Bh6 Qxa4 28. Qf4 Qd7 29. Ng3 Bxh6 30. Qxh6 Qe8 31. h3 Bd7 32. Re1 Qf8 33. Qe3 Re8 34. Ra1 Qf7 35. Ra7 Bc8 36. Ne4 Qg6 37. Kh2 Kf8 38. f4 Kg8 39. Rc7 Kf8 40. Ng3 Bf5 41. Qd4 Rc8 42. Ra7 Kf7 43. Qe3 Re8 44. Qf3 Rg8 45. Qe3 Re8 1/2-1/2

9 Bxg5 Nxe4 10 Bf4 Nf6

Black's strongest move by far, giving him an enormous 87% success rate in practice! The most common moves, however, are either 10...Qa5 or 10...Bg7, after which the play can get quite messy. A sample game with the former ran 10...Qa5 11. Bc4 Bg7 12. Qe2 b3+ 13. Kf1 f5 14. f3 O-O 15. fxe4 fxe4 16. g3 Qxa2 17. Rxa2 bxa2 18. Bxa2 Rxa2 19. Qxe4 Ba6 20. Nh3 Rxb2 21. Ke1 Bxb5 22. Kd1 Nd7 23. Ng5 Nf6 24. Qe6+ Kh8 25. Re1 Ba4+ 26. Kc1 Rc2+ 27. Kd1 Rxh2+ 28. Kc1 Rc2+ 29. Kd1 Rh2+ 30. Kc1 1/2-1/2.

A game with 10...Bg7 ran 10...Bg7 11. Qe2 Nf6 12. Nxd6+ Kf8 13. Nxc8 Qxc8 14. d6 exd6 15. Bxd6+ Kg8 16. Nf3 Nbd7 17. Qc4 Nb6 18. Qxc5 Qe6+ 19. Be2 Nbd7 20. Qxb4 Nd5 21. Qb7 Re8 22. O-O Qxd6 23. Bc4 N5b6 24. Rad1 Qc5 25. Rxd7 Nxc4 26. Rxf7 Bxb2 27. Rc7 Qb6 28. Qd5+ 1-0

11. Bc4 Bg7 12. Nf3 O-O 13. O-O Nbd7 14. Qc1!

The only move which doesn't lose. White must insist on active counterplay here, as his embattled knight on b5 is a goner.

 Nb6 15. Bd3 Ba6 16. Bh6 c4

If black plays 16...Bxh6, white may be able to pursue a successful attack, e.g., 17 Qxh6 c4 18 Bb1 Bxb5 19 Ng5 and black cannot protect his P/h7. White has at least the draw in hand here with 20 Bxh7+ Kh8 etc., but 20 Nxh7! challenges black to find the key defensive move ...Nbd7, instead of the tempting ...Nbxd5. An amusing defensive try is 20...Ng8 21. Qh5 c3 22. Nf6+ Kg7 23. Qg5+ Kh8 24. Qh4+ Kg7 25. Nh5+ Kh6 26. Ng3+ Kg7 27. Nf5+ Kg6 28. Qg4+ Kh7 29. Qg7# 1-0. 

Another amusing line is 19...Nbxd5 20. Rd1 Bc6 21. Nxh7 Qb6 22. Rxd5 Nxd5 23. Nxf8 Nf6 24. Bh7+ Kh8 25. Bf5+ Kg8 26. Ne6 fxe6 27. Bxe6# 1-0. The white rook eliminates the key black defender, the knight on d5.

Best for black may be 16...Kh8, when it is not clear how white should proceed.


17. Qg5 Ne8 18. Bxg7 Nxg7 19. Bxh7+ Kxh7 20. Qh4+ Kg6 21. Qg5+ Kh7 22. Qh4+ Kg6 23. Qg4+ Kh6 24. Qh4+ Kg6 25. Qg5+ 1/2-1/2


Wednesday, December 21, 2016

December Toledo Swiss

Round 1, Charisee Woods(1531)-chessart(1800)

1 e4 c5 2 c3 d5

For my money the strongest move, though other moves score just as well or slightly better.

3 ed Qxd5 4 Nf3 Nf6 5 d3(?)

Normal is 5 d4.

5...g6

This leaves the database.

6 Bf4 Bg7 7 Be2 0-0 8 Qd2 Nc6 9 Na3 Nh5 10 Bg3 NxB 11 hg Bf5 12 Nc2 Rfd8 13 Ne3 Qd7 14 Rd1 b5 15 NxB QxN 16 Ng5 h6 17 Ne4 b4 18 g4 Qe5 19 f4 Qd5 20 Bf3 Qxa2 21 Nxc5 bc 22 bc QxQ 23 RxQ Bxc3 24 BxN Rc8 25 Nb7 Rxd3 26 Be4 RxR 27 Kf1 Bd4 28 Ke1 Be3 29 Rxh6 Re1#
                                                ****************

In round two I played a 12-year old Expert! After beating me he went on to beat a Master, and then in the 4th round lost to the other Master in the tournament.

Round 2, chessart(1800)-Justin Sun Liang(2057)

1 d4 d5 2 c4 c6 3 cd cd 4 Nc3 Nc6 5 Bf4 Nf6 6 e3 a6

The point here is to prevent white's Bb5, threatening to trade B for N and  leave black with a bad bishop. After 6...Bg4, an amusing miniature runs  1. d4   Nf6 2. c4   c6 3. Nc3  d5 4. cxd5 cxd5 5. Bf4  Nc6
6. e3   Bg4 7. Qb3  Qd7 8. h3   Na5 9. Qb5  Qxb5 10. Nxb5 Bh5 11. g4 1-0.

Another sample game, this time with 6...Bf5 rather than 6...Bg4, runs 1. d4 d5 2. c4 c6 3. cxd5 cxd5 4. Bf4 Nc6 5. e3 Nf6 6. Nc3 Bf5 7. Qb3 Na5 8. Qa4+ Bd7 9. Qc2 e6 10. Bd3 Rc8 11. Nf3 b5 12. a3 Be7 13. Ne5 Nc4 14. Qe2 O-O 15. O-O Nxa3 16. Nxd7 Qxd7 17. Nxb5 Nc4 18. Nxa7 Ra8 19. b3 Bd6 20. bxc4 Bxf4 21. Nb5 Rxa1 22. Rxa1 dxc4 23. Bxc4 Bb8 24. g3 Ne4 25. Bd3 Nd6 26. Nc3 g6 27. Na4 Qe7 28. Nc5 Rd8 29. Qb2 e5 30. Na6 Ba7 31. Nb4 Qb7 32. Rxa7 Qxa7 33. Nc6 Qa8 34. Nxd8 e4 35. Nb7 exd3 36. Nxd6 Qc6 1-0

 7 a3?

Normal is 7 Bd3, which leaves white with a healthy advantage. My move allows black to develop his bad bishop.

7...Bf5 8 Bd3 BxB 9 QxB Na5

Normal is 9...e6. Black's move is not in the database.

10 b4 Nc4 11 Nf3 e6 12 0-90   Bd6 13 BxB NxB 14 Rfc1 0-0 15 Nd2 Rc8 16 Na4 Nc4 17 NxN?

Getting too careless. I should have asked myself why he was letting me win a pawn. The computer likes 17 Nc5, after which I retain a small advantage.

17...dc 18 RxP? RxR 19 QxR b5 20 Qc6 ba 21 Qxa6 Qd7 22 Rc1 Nd5 23 b5 Rb8 24 Qxa4 h6 25 Rc5 Nc7 26 Qa7 Rxb5 27 h3 Rb1+ 28 Kh2 Qd6+ 29 g3 Ne8 30 Qa8 Rb8 31 Qa7 Qb6 32 Qa4 Nf6 33 Qc2 Qa6 34 a4 g6 35 a5 Kg7 36 Kg2 Rb5 37 RxR QxR 38 Qc5 QxQ 39 dc Nd5 40 a6 Kf6 41 Kf3! Ke5 41 a7 Nc7 0-1
 
Round 3, Alan Bui(1573)-chessart(1800)

1 d4 Nf6 2 Nf3 c5 3 c3 e6 4 Bf4 d5?

A serious mistake, as it lets white play the Colle-type attack which he seeks. All other reasonable moves give black a huge advantage. The strongest is 4...b6, which has black winning twice as often as white. A sample game runs 1. d4 Nf6 2. Nf3 e6 3. Bf4 c5 4. e3 b6 5. Nbd2 Be7 6. h3 Bb7 7. c3 O-O 8. Bd3 Nc6 9. O-O d6 10. Qe2 cxd4 11. exd4 Qd7 12. Rfe1 Rfe8 13. Ne4 Nxe4 14. Bxe4 g6 15. Rad1 Bf8 16. Qb5 d5 17. Bb1 Bg7 18. a4 Qc8 19. Qe2 Ba6 20. Qe3 Na5 21. Bh6 Nc4 22. Qc1 Bh8 23. Ne5 Nd6 24. Ng4 f6 25. h4 Qd7 26. Qf4 Nf5 27. Bxf5 exf5 28. Ne3 Re4 29. Qg3 Rae8 30. f3 R4e7 31. b3 Bg7 32. Bxg7 Kxg7 33. Nc2 Be2 34. Rd2 Qc8 35. Qf2 Ba6 36. Rxe7+ Rxe7 37. Nb4 Bb7 38. Rd3 f4 39. Qd2 a5 40. Nc2 Ba6 41. c4 dxc4 42. bxc4 Qxc4 0-1  The point is not that black got a great game out of the opening, but that he got a playable middlegame, which should always be black's goal.

f e3 Bd6 6 Bg3 0-0 7 Bd3 h6?

 Here again, 7...b6 yields good results.

8 Nbd2 Qc7 9 Ne5 Nfd7 10 f4 f6 11 Ng6 Re8 12 Qh5 and 1-0 in 20 moves