How to Beat Chess Computers

This guide to beating Chess computers might help you to win a bit more often against Chess computers. A few things that really help are to be able to understand how they work and think, be able to predict what sorts of things they might not see and to understand what parts of the game a computer is better than humans at playing.

How the Computer decides who is ahead

A Chess computer assesses who is ahead in a slightly different way to how many human players would. The piece values are the same but not all humans would consider some of the other factors that a computer does. A computer uses a scoring algorithm similar to the one set out below, but this will vary depending on the computer:

Queen = 9 points
Rook = 5 points
Bishop = 3 points
Knight = 3 points
Pawn = 1 point
King = Between 41 and 200 points (it needs to be large enough so that it doesn’t get exchanged off by mistake)

Doubled Pawns = -0.5 points
Isolated Pawn = -0.5 points
Backward Pawn = -0.5 points

Any available move = 0.1 points as it is better to have more available moves than your opponent.

Factors such as weak pawns near the king should be penalised.

Well placed pieces, passed pawns, certain attacks and pins should be added to the score.

The computer subtracts your score from its own score. A positive score means the computer is ahead and a negative score means that the human is ahead.

Openings

A good Chess computer will have a large openings database. For more common openings such as the Ruy Lopez, Giuoco Piano, Queen’s Gambit and the Sicilian Defense, a computer will have a database containing up to about white and black’s first 20 moves of many variations of these openings. Therefore in a timed game, a computer will not need to use up any time at all if the human opponent sticks to the moves in the computer’s database so it will give the computer much more time in the middle and end games to do larger and deeper searches.

One possible tip is to play an unusual opening that will not be in the computer’s database. In a timed game, this makes the computer start using up its time right from the start of the game which gives it less time later on in the game to do larger and deeper move searches. So if you happen to be an expert on the Hippopotamus Defense or some other unusual opening then you will probably know that opening better than the computer does. It only takes one move not in its database and the computer will need to start using up it’s time doing large searches very early on in the game.

An example of this is supposing the time limit of a game is 40 moves in 2 hours before the time control. If the computer can play the first 20 moves directly from its database, it will then only have to start doing searches for move 21 onwards. Therefore it will only have to make 20 moves in the 2 hours which is about 6 minutes a move on average but if the computer only had about 5 moves of a particular opening in its database then it will have to make 35 moves in 2 hours which is about 3 and a half minutes a move on average. This affects the standard of play that the computer can play because it reduces the search depths that the computer can do during the game.

Middle Game

For a Chess computer the middle game begins as soon its opening database can no longer be used. In the middle game there are usually about 30 to 40 moves possible on each move. This is known as the branching factor and the larger this is then the larger the search needed. When the computer is searching for moves, it will therefore need to search about 1000 positions for one move from each player, 1000000 positions for two moves from each player, 1000000000 for three moves from each player and so on. The depth of the search that it can do depends on the speed of the computer and on the amount of time it has available to move.

The search algorithm that most of the more modern Chess computers use is called the Selective Iterative-Deepening Search. This searching algorithm searches all possible moves to a depth of one first, then all possible moves to a depth of two, then all possible moves to a depth of three and so on. If the computer calculates that there is a Checkmate or a loss of its queen for example then it terminates that branch of the search. This means that the computer doesn’t have to continue searching a large number of moves from that branch, so it can use its memory to search to a greater depth on other branches of the search tree.

A tip is that if for example you sacrificed your queen knowing that in three moves time you could get checkmate using other pieces then that branch of the tree might get terminated by the computer before it realises that its just fell for a mate in 3 which it now can’t avoid. Some computers might not fall for this however as the very best computers would have still continued searching that branch of the search.

The depth that the computer searches to depends on how much time it has left. Looking at the example from the openings above about the computer having less time if it doesn’t know the opening, this might reduce a search from about 12 plies to 10 plies (where 1 ply is a move from one player, 2 plies is one move from each player) on each move. This could help reduce the standard of play of the computer.

One thing that better computers do is think during your time. If you therefore take about 15 minutes on one move you may find that the computer has already searched that move to a depth of about 13 plies. So a tip is to try and avoid taking this long over a move unless it really is necessary to take this long.

Transition Tables

Some of the better Chess computers use transition tables. They are used to remember some of the best lines from its previous searches and recent positions. So if you had a position and then two moves later that exact position was repeated then the computer would still have the best moves still stored in memory in a transition table.

A tip then is try to avoid repetition (unless you are playing for 3 move repetition to get a draw) as the computer will probably have a recent position stored in memory and will be able to move instantly, which gives it more time to search on other moves.

End Games

Chess computers have databases of all 3, 4 and 5 piece end games so they often don’t need to use up as much time as you might expect them to in the end game. An end game like this favours the computer because of its database and also the branching factor on each move is reduced once pieces like the queens are exchanged off, so the computer can search to a greater depth than in the middle game while still using the same amount of time as it would in the middle game. Deep Blue can sometimes do searches of up to a depth of about 40 plies in the end game while chess programs that you may use at home such as Chessmaster might search up to a depth of about 20 plies on its highest skill levels.

A tip is to try your best to avoid exchanging off pieces unless it really does help out your position. The branching factor on each move should be kept higher to force the computer into doing shorter searches on each move.

Example Games

There is a German player called Eduard Nemeth, who although is only rated about 2100, is extremely good at beating Chess Computers. He uses a combination of strange unorthodox openings, which take the computer out of its opening book very early on in the game, piece sacrifices and a common bishop sacrifice that opens up the h file. Also notice how the games are always won before the end game, its unlikely a player rated around 2100 could compete with this standard of chess computer in the end game. The following games are some of his wins against some of the top Chess computers.

Time Limit: 30 mins each
White: Shredder 5
Black: Eduard Nemeth

1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 4. Ba4 f6 5. d4 d6 6. c3 h5 7. Be3 Bg4 8. O-O Be7 9. d5 b5 10. Bc2 Na7 11. a4 f5 12. h3 f4 13. Bxa7 Rxa7 14. hxg4 hxg4 15. Nfd2 Nh6 16. axb5 Bf8 17. g3 Qg5 18. Ba4 Qh5 19. Nf3 Nf5 20. Nh4 Nxh4 21. bxa6+ Ke7 22. Re1 Nf5 23. Kf1 f3 0-1

Time Limit: 5 mins each
White: Fritz 6
Black: Eduard Nemeth

1. d4 h5 2. e4 e5 3. dxe5 Nc6 4. Nf3 Be7 5. Nc3 a6 6. Bc4 Nh6 7. O-O d6 8. exd6 Bxd6 9. Bd5 Bg4 10. Bxc6+ bxc6 11. h3 Qe7 12. hxg4 hxg4 13. Bg5 f6 14. e5 Qf7 15. exd6 O-O-O 16. Ne5 fxe5 17. Bxd8 Qh5 18. f3 g3 19. Re1 Ng4 20. Kf1 Qh1+ 21. Ke2 Qxg2+ 22. Kd3 Nf2+ 23. Kc4 Nxd1 24. Raxd1 Rxd8 0-1

Time Limit: 5 mins each
White: Eduard Nemeth
Black: Junior 6.0

1. Nc3 d5 2. d3 e5 3. e4 d4 4. Nb1 Nc6 5. g3 Nf6 6. h4 Be7 7. Bh3 O-O 8. b3 Bxh3 9. Nxh3 h6 10. a3 a5 11. Kf1 a4 12. Bg5 axb3 13. cxb3 hxg5 14. hxg5 Nb4 15. Kg2 Ne8 16. Qh5 f5 17. g6 Nf6 18. Qh4 Rf7 19. Ng5 Kf8 20. Qh8+ Ng8 21. Qxg8+ Kxg8 22. gxf7+ Kf8 23. Rh8++ Mate 1-0

Time Limit: 5 mins each
White: Eduard Nemeth
Black: Fritz 6

1. e4 c5 2. c4 g6 3. Nc3 Bg7 4. h4 Nf6 5. d3 d6 6. Nh3 Nc6 7. Bg5 O-O 8. Be2 h6 9. Be3 Nd4 10. Qd2 h5 11. Bh6 Bxh6 12. Qxh6 Nc2+ 13. Kd2 Nxa1 14. Ng5 Qb6 15. Kc1 e6 16. g4 hxg4 17. h5 Nb3+ 18. axb3 Qa5 19. Kb1 Qxc3 20. bxc3 1-0

Time Limit: 10 mins each
White: Eduard Nemeth
Black: Fritz 6

1. e4 c5 2. e5 Nc6 3. f4 g5 4. Bc4 gxf4 5. d4 cxd4 6. c3 dxc3 7. Bxf7+ Kxf7 8. Qh5+ Ke6 9. Qh3+ Kxe5 10. Bxf4+ Kxf4 11. Qh5 Qa5 12. Ne2+ Ke4 13. Nbxc3+ 1-0

Time Limit: 10 mins each
White: Eduard Nemeth
Black: Hiarcs 7.32

1. e4 c5 2. Na3 Nc6 3. d4 cxd4 4. Bc4 Nf6 5. h3 Nxe4 6. Bxf7+ Kxf7 7. Qh5+ Ke6 8. Qg4+ Kd5 9. c4+ dxc3 10. Be3 Ne5 11. O-O-O+ Nd2 12. Qe2 Qa5 13. Bxd2 cxd2+ 14. Rxd2+ Ke6 15. f4 Kf6 16. fxe5+ Qxe5 17. Qf2+ Kg6 18. Nf3 Qf6 19. Nb5 Qf4 20. g3 Qc4+ 21. Rc2 Qxb5 22. Nh4+ Kh6 23. Rc5 Qxc5+ 24. Qxc5 e6 25. Qe3+ g5 26. Rf1 Bg7 27. Nf5+ Kg6 28. Nxg7 Kxg7 1-0

Time Limit: 10 mins each
White: Eduard Nemeth
Black: Junior 6.0

1. e4 c5 2. Na3 Nc6 3. d4 cxd4 4. Bc4 Nf6 5. h3 Nxe4 6. Bxf7+ Kxf7 7. Qh5+ Ke6 8. Qg4+ Kd5 9. c4+ dxc3 10. Be3 Ne511. O-O-O+ Nd2 12. Qe2 d6 13. Bxd2 cxd2+ 14. Rxd2+ Kc6 15. f4 Nd7 16. Rc2+ Nc5 17. b4 e6 18. bxc5 dxc5 19. Nf3 Qf6 20. Ne5+ Kc7 21. Qe3 a6 22. Rd1 Kb8 23. Nac4 Ka7 24. Nd6 Rb8 25. Qxc5+ Ka8 26. Nec4 Qxf4+ 27. Kb1 Qxc4 28. Qxc4 1-0

Time Limit: 10 mins each
White: Eduard Nemeth
Black: Crafty 18.10

1. e4 c5 2. Na3 Nc6 3. d4 cxd4 4. Bc4 Nf6 5. h3 Nxe4 6. Bxf7+ Kxf7 7. Qh5+ Ke6 8. Qg4+ Kd5 9. c4+ dxc3 10. Be3 e5 11. Rd1+ Nd4 12. Bxd4 exd4 13. Qf5+ Kc6 14. Qxe4+ d5 15. Qxd4 Qa5 16. Rc1 Bb4 17. Nf3 Re8+ 18. Ne5+ Rxe5+ 19. Qxe5 Kb6 20. O-O cxb2 21. Qxb2 Qxa3 22. Qd4+ Ka6 23. Rb1 Bf8 24. Qxd5 Qc5 25. Qd3+ b5 26. Rfc1 Qf5 27. Rc6+ Ka5 28. Qd8+ Ka4 29. Qd1+ Ka5 30. a4 Bd7 31. Rxb5+ Qxb5 32. axb5 Bxc6 33. bxc6 1-0

Time Limit: 10 mins each
White: Eduard Nemeth
Black: Deep Fritz

1. e4 c5 2. Na3 Nc6 3. d4 cxd4 4. Bc4 Nf6 5. h3 Nxe4 6. Bxf7+ Kxf7 7. Qh5+ Ke6 8. Qg4+ Kd5 9. c4+ dxc3 10. Bf4 e5 11. O-O-O+ Nd4 12. Rxd4+ Kxd4 13. Nf3+ Kd5 14. Rd1+ Kc6 15. Nxe5+ Kb6 16. Nec4+ Kc5 17. Be3+ Kc6 18. Qxe4+ d5 19. Ne5+ Kc7 20. Nb5+ Kb8 21. Rxd5 Bd6 22. Nxd6 1-0

Time Limit: 10 mins each
White: Eduard Nemeth
Black: Chess Tiger 14.0

1. e4 c5 2. Na3 Nc6 3. d4 cxd4 4. Bc4 Nf6 5. f4 Nxe4 6. Bxf7+ Kxf7 7. Qh5+ Kf6 8. Qh4+ g5 9. fxg5+ Ke5 10. Qf4+ Kd5 11. c4+ dxc3 12. Be3 Ne5 13. O-O-O+ Nd2 14. Qd4+ Ke6 15. Qxc3 Ne4 16. Qb3+ Kf5 17. g4+ Kg6 18. Qd5 Qc7+ 19. Kb1 Nxg5 20. Nb5 Qb8 21. Bxg5 e6 22. Qe4+ Kxg5 23. Nf3+ Nxf3 24. Qxf3 h5 25. gxh5 Qe5 26. Nd6 Kh6 27. Nf7+ 1-0

Time Limit: 40 moves in 120 minutes
White: Eduard Nemeth
Black: Genius 5

1. h4 e5 2. e4 Nf6 3. b4 Bxb4 4. Nc3 Bxc3 5. dxc3 O-O 6. Bg5 d6 7. Nh3 h6 8. Bd3 hxg5 9. hxg5 Bg4 10. f3 Bxh3 11. Rxh3 Nfd7 12. f4 g6 13. Qg4 Kg7 14. O-O-O Rh8 15. Rdh1 Rxh3 16. Qxh3 Kf8 17. Bc4 Qe8 18. f5 Ke7 19. f6+ Kd8 20. Qh7 d5 21. Bxd5 c6 22. Bxf7 Qf8 23. Rd1 Kc8 24. Be6 Qd8 25. Qxg6 Kc7 26. Qf5 Qf8 27. Bxd7 1-0

Summary

These are some of the key points about Chess computers and how to beat them.

1. Playing an unusual opening can reduce the depth of the searches made by the computer in the middle and end game in a timed match.

2. If you avoid exchanging off pieces unnecessarily then the computer has to do larger searches which will be to a shorter depth.

3. Think about sacrifices that might benefit you if the computer accepts them and doesn’t search that branch far enough to see what your plan really is. Be careful with this though as some computers will continue to search all branches.

4. Against better computers, the computer will be using your move time to think about it’s reply so the longer you take to decide on your move then the longer the computer has had to calculate the best reply.

5. Unless your end game is excellent, avoid end games whenever possible as Chess computers can do extremely large searches in the end game.

6. Avoid repetition of moves as this allows computers which use transition tables to save a lot of time as they can move instantly when they already have the position and best moves to play stored in a transition table.

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