2x bishop checkmate?

[stormbind]

Having failed to beat the computer despite making huge changes to the way I aproach the board, I tried reading one of Lasker's games for inspiration.

It has led to my best ever result against the computer (with the clock): my 2x bishops against nothing. I thought this scenario was probably a doable checkmate, but I cannot find the solution!

If it can be done, and ignoring the fact that I'm currently stumped, it will be my first ever 1-0 victory over the computer in completely fair conditions. Given the draw I got off it last time, this would be match point - and thus something very much sought after.

 

[stormbind]

Got it, but I might have cheated because to try out some things I moved it's king..

Here's the PGN.. 97 moves!

[Event "Practice vs Computer"]
[Variant "Chess"]
[Result "1-0"]

1. e4 c5 2. f4 e5 3. d3 Nc6 4. Nf3 Bd6 5. g3 Nf6 6. b3 exf4 7. gxf4 o-o 8. e5 Re8 9. Be2 Bxe5 10. fxe5 Nxe5 11. o-o Nxf3+ 12. Rxf3 d5 13. Nc3 d4 14. Ne4 Nxe4 15. dxe4 Rxe4 16. Bd3 Re8 17. Rf4 Re5 18. Qf3 f6 19. Bc4+ Kh8 20. Ba3 Qb6 21. Re4 Rg5+ 22. Kf2 Bf5 23. Bd3 Bxe4 24. Qxe4 Rh5 25. Re1 Rg8 26. Qg4 Rxh2+ 27. Kg1 Rh6 28. Bc1 g5 29. Bc4 Rf8 30. Qd7 Qc6 31. Qxc6 bxc6 32. Re6 Rh3 33. Rxc6 Rg3+ 34. Kf2 Rg4 35. Rxc5 h6 36. Ra5 Rh4 37. Rxa7 Rh2+ 38. Ke1 Rxc2 39. Bd2 Rb2 40. Kd1 Rb1+ 41. Bc1 d3 42. Kd2 Rd8 43. Rf7 Ra1 44. Rxf6 Rxa2+ 45. Kd1 Kg7 46. Ra6 Rxa6 47. Bxa6 h5 48. Bxg5 Rd6 49. Bc4 Kg6 50. Bf4 Rd7 51. Kd2 Kf5 52. Bg3 Ke4 53. Bb5 Rd8 54. Bh4 Rd6 55. b4 Rd4 56. Bc6+ Kf5 57. Be7 Ke5 58. Bc5 Rd8 59. b5 h4 60. b6 Rc8 61. b7 Rd8 62. Be7 Rb8 63. Bxh4 Kd6 64. Be4 Rh8 65. Bg3+ Kc5 66. b8=Q Rxb8 67. Bxb8 Kd4 68. Bxd3 Kc5 69. Kc3 Kd5 70. Bb1 Ke6 71. Kd4 Ke7 72. Ke5 Kd7 73. Be4 Kc8 74. Ba7 Kd7 75. Bb6 Ke7 76. Bd5 Kd7 77. Bc5 Kc7 78. Ke6 Kb8 79. Kd6 Kc8 80. Bb6 Kb8 81. Kc6 Kc8 82. Be6+ Kb8 83. Bc7+ Ka7 84. Bc4 Ka8 85. Ba6 Ka7 86. Bc8 Ka8 87. Kb5 Ka7 88. Bd6 Ka8 89. Kc6 Ka7 90. Bc7 Ka8 91. Bb6 Kb8 92. Kd7 Ka8 93. Ba5 Kb8 94. Kd8 Ka7 95. Kc7 Ka8 96. Bb7+ Ka7 97. Bb6+

 

[Richard Cribb]

Got it, but I might have cheated because to try out some things I moved it's king..

Here's the PGN.. 97 moves!

[Event "Practice vs Computer"]
[Variant "Chess"]
[Result "1-0"]

1. e4 c5 2. f4 e5 3. d3 Nc6 4. Nf3 Bd6 5. g3 Nf6 6. b3 exf4 7. gxf4 o-o 8. e5 Re8 9. Be2 Bxe5 10. fxe5 Nxe5 11. o-o Nxf3+ 12. Rxf3 d5 13. Nc3 d4 14. Ne4 Nxe4 15. dxe4 Rxe4 16. Bd3 Re8 17. Rf4 Re5 18. Qf3 f6 19. Bc4+ Kh8 20. Ba3 Qb6 21. Re4 Rg5+ 22. Kf2 Bf5 23. Bd3 Bxe4 24. Qxe4 Rh5 25. Re1 Rg8 26. Qg4 Rxh2+ 27. Kg1 Rh6 28. Bc1 g5 29. Bc4 Rf8 30. Qd7 Qc6 31. Qxc6 bxc6 32. Re6 Rh3 33. Rxc6 Rg3+ 34. Kf2 Rg4 35. Rxc5 h6 36. Ra5 Rh4 37. Rxa7 Rh2+ 38. Ke1 Rxc2 39. Bd2 Rb2 40. Kd1 Rb1+ 41. Bc1 d3 42. Kd2 Rd8 43. Rf7 Ra1 44. Rxf6 Rxa2+ 45. Kd1 Kg7 46. Ra6 Rxa6 47. Bxa6 h5 48. Bxg5 Rd6 49. Bc4 Kg6 50. Bf4 Rd7 51. Kd2 Kf5 52. Bg3 Ke4 53. Bb5 Rd8 54. Bh4 Rd6 55. b4 Rd4 56. Bc6+ Kf5 57. Be7 Ke5 58. Bc5 Rd8 59. b5 h4 60. b6 Rc8 61. b7 Rd8 62. Be7 Rb8 63. Bxh4 Kd6 64. Be4 Rh8 65. Bg3+ Kc5 66. b8=Q Rxb8 67. Bxb8 Kd4 68. Bxd3 Kc5 69. Kc3 Kd5 70. Bb1 Ke6 71. Kd4 Ke7 72. Ke5 Kd7 73. Be4 Kc8 74. Ba7 Kd7 75. Bb6 Ke7 76. Bd5 Kd7 77. Bc5 Kc7 78. Ke6 Kb8 79. Kd6 Kc8 80. Bb6 Kb8 81. Kc6 Kc8 82. Be6+ Kb8 83. Bc7+ Ka7 84. Bc4 Ka8 85. Ba6 Ka7 86. Bc8 Ka8 87. Kb5 Ka7 88. Bd6 Ka8 89. Kc6 Ka7 90. Bc7 Ka8 91. Bb6 Kb8 92. Kd7 Ka8 93. Ba5 Kb8 94. Kd8 Ka7 95. Kc7 Ka8 96. Bb7+ Ka7 97. Bb6+

Congratulations!
I will have a closer look at it later.

 

[stormbind]

I have looked at the game now, and think my oponent was missing a few logic gates

Move 47.. h5 looks obviously flawed. I had the computer redo that, and it persisted to make the same move. On further investigation, it only does this when ply depth is between 7 and 10 (this game is against the clock, where ply depth varies)

 

[Soviet]

it's possible to mate with two bishops

it's a pain in the sphincter and I never bothered to memorize it, I probably should have...same with bishop and knight vs. king...so far i've never had it happen in a game thankfully

 

[punkbass2000]

2 bishop mate isn't that bad, IMO, but yes, the Kn + B mate can easily take 30 turns if your king is off center and your knight is at the edge. I'm not sure I could do it in the requisite 50 moves necessarily right now. I recall trying it vs. a friend once when I was ~8, without any knowledge of chess checkmates just to see if we could. We deduced it was not possible .

 

[Richard Cribb]

2 bishop mate isn't that bad, IMO, but yes, the Kn + B mate can easily take 30 turns if your king is off center and your knight is at the edge. I'm not sure I could do it in the requisite 50 moves necessarily right now. I recall trying it vs. a friend once when I was ~8, without any knowledge of chess checkmates just to see if we could. We deduced it was not possible .

I agree. Two bishops are fairly easy, Kn + B is a nightmare. The difference, a very important one, is that while you just need to get the king in to a corner - any corner - with two bishops, with Kn + B you need to get him into one corner of the same colour as your remaining bishop.
I had to do this in a game I played in 1982(!!) in a junior tournament. I hadn't studied it so thoroughly, the only thing I did remember at this occasion was what I mentioned above. I managed in about 40 moves, but I started out on the wrong track.
By the way, I regard it as one of the injustices in chess that king and two knights against king is a draw... That's horsepower for you!

 

[punkbass2000]

By the way, I regard it as one of the injustices in chess that king and two knights against king is a draw... That's horsepower for you!

I completely agree. They're (technically) more powerful than a rook, yet a rook mate is simplicity itself!

 

[Ribannah]

Perhaps it is a consolation that you can force a mate with 3 knights.
Unless they get forked, that is.

C'mon guys, these are just the elementary endgames!

Move 47.. h5 looks obviously flawed.

Hardly. The AI tries to save pawn d3. Many of the 46 previous moves on either side are far worse.

 

[Narz]

It's good to practice these endgames once in awhile. Believe it or not, even the endgame King & Queen vs. King & Rook can be tricky against a strong opponent.

 

[Perfection]

I once won a tournament game where my opponant who ran out of time trying to mate me in said fashion

 

[Narz]

I once won a tournament game where my opponant who ran out of time trying to mate me in said fashion

Sucks for him.

It pays to practice a bit so you can do it under time pressure.

Hey Perf, what's your rating?

I haven't played in years. Mine, I think, is about 1300. Maybe I'll keep it low by not entering tournaments and then enter a big one with an U1400 prize of $1,000 or something.

 

[Perfection]

I never keep track of my rating. I prefer to remain an enigma. (That and I'm really freakin' lazy)

 

[Narz]

Actually, I searched my name. Looks like I am unrated again. I guess if you don't play in tournaments for a few years and let your USCF membership expire they reset you.

I never keep track of my rating. I prefer to remain an enigma. (That and I'm really freakin' lazy)

What kind of tournaments you play in? Big, small? Ever won any money?

 

[Aphex_Twin]

I never keep track of my rating. I prefer to remain an enigma. (That and I'm really freakin' lazy)

From your games, and taking some lee-way, I would say you are ~ Elo 1300-1350.

 

[Millman]

Try two knights, king vs. king and enemy pawn.

My favorite are those simple rook endings, rook and five pawns vs. four but your king is on f3 instead of e3 so it is a book draw, but your opponent puts his rook on the second rank instead of first and you win instead.

 

[Bluemofia]

I once won a tournament game where my opponant who ran out of time trying to mate me in said fashion

But, did you have the right pieces to checkmate? Otherwise it would be a draw.

To win on time, the opponent must have no time left, and you must have sufficient pieces to possibly checkmate the opponent.

 

[Millman]

But, did you have the right pieces to checkmate? Otherwise it would be a draw.

To win on time, the opponent must have no time left, and you must have sufficient pieces to possibly checkmate the opponent.

K & Q vs. K & R, any player can declare the win if their opponent has ran out on time. In tournaments I think there is a five second delay, so that means, if you had 2 seconds left, you can automatically play to fifty moves and declare it a draw there if you want to be technical. There are some complex endings that are almost simple where someone has lost on time because they couldn't finish it, although it look like it was going to be a draw.

I played in a tournament recently and saw someone lose being a Queen up, it was a technical draw because it was the 'bishop' pawn on the seventh rank, and the Queen couldn't win, but still lost on time because he didn't take the pawn.