Stable engines, rating of CCRL 2000 or CEGT 1850, or less

[Ferdy]

These are the engines that I have tried so far:
1. Gerbil 0.2 (stable)
2. TSCP 1.81d ja (stable)
3. Olivechess 0.2.7 (not stable, with memory leak)
4. Mint v2.3 (stable, but could not recognize pawn captures rook promote to knight)

Is there other stable engines you can recommend, uci or winboard, for windows?

I am developing a new engine with a goal to make it play positional moves (don't care the tactics), I am not interested on increasing its strength but instead try to lower it so that its move would look positional to a club player level.

This engine is based on Deuterium, but without nullmove, no reductions and prunings, only check extension, no egbb, but with hashing, evaluation is re-written. Changes in the eval so far:
1. piece values
2. pst
3. knight, bishop, and rook mobilities
4. passer
5. doubled, isolated, backward pawns
6. basic king shelter
7. rook in open file
8. rook in 7th rank
9. 2 bishops advantage
10. bonus for knight behind pawn
11. pawn and bishop colors scoring

The program is still strong, it can beat Gerbil but also loses for example, Mint and TSCP have difficulties beating it so far. I am trying to reduce its strength by adding more knowledge and computation time in the eval. I am holding implementation of null move and LMR. Perhaps implement null move with high reduction so that it will miss on some interesting positions.

Sample game vs me.

[pgn]
[Event "Computer Chess Game"]
[Site "INTEL-PC"]
[Date "2015.02.15"]
[Round "-"]
[White "Me"]
[Black "CDrill 1200"]
[Result "0-1"]
[TimeControl "300+1"]
[Annotator "1... +0.05"]

1. d4 Nf6 {+0.05/8 13} 2. c4 e6 {+0.01/8 12} 3. Nc3 d5 {+0.02/8 11} 4. Bg5
dxc4 {+0.05/8 10} 5. e4 Nc6 {+0.11/8 10} 6. Nf3 h6 {+0.10/8 9} 7. Bxf6 Qxf6
{+0.11/8 9} 8. Bxc4 a6 {+0.05/7 9} 9. O-O b5 {+0.22/8 8} 10. d5 Nb4
{+0.31/7 8} 11. Be2 exd5 {+0.24/7 8} 12. exd5 c6 {+0.31/7 8} 13. a3 Nxd5
{+0.32/8 7} 14. Nxd5 cxd5 {+0.34/8 7} 15. Qxd5 Rb8 {+0.28/7 7} 16. Rfe1 Be7
{+0.21/7 7} 17. Bd3 Bb7 {+0.33/7 7} 18. Rxe7+ Qxe7 {+1.78/8 6} 19. Qf5 Bc8
{+1.78/8 6} 20. Qf4 Rb7 {+1.71/7 6} 21. Re1 Be6 {+1.47/7 6} 22. Be4 Rb6
{+1.68/7 6} 23. Nd4 O-O {+1.65/7 6} 24. Bb1 Qd8 {+1.77/7 5} 25. h4 Bc4
{+1.88/7 5} 26. Nf5 Qf6 {+1.90/7 5} 27. Qe4 g6 {+2.14/8 5} 28. Nxh6+ Kg7
{+2.09/8 5} 29. Ng4 Qxb2 {+2.17/8 5} 30. h5 Re6 {+2.98/7 5} 31. h6+ Kh7
{+3.08/8 5} 32. Ne5 Qd2 {+3.18/7 4} 33. f4 Bd5 {+3.99/7 4}
{Black wins on time} 0-1
[/pgn]

[Modern Times]

Testers have a very low tolerance level for unstable engines, so 99% of the engines you see on the CCRL list are stable. There are lots of engines below that level on the blitz list.

[Adam Hair]

This list is from memory. I have not used these engines in a while, and the GUI I used for them was primarily Arena 2.0.1. But I do not recall having problems with the following engines:

SamChess
Surprise 4.3b13
Roce 0.0390
Rocinante 2.0 64-bit (mcts)
Adamant 1.7
GChess IV 0.2.0
Kitteneitor 0.22.1
Bace 0.45
Cmcchess 2.5
MSCP 1.44

I believe that you can find links to all of these engines at the Computer Chess Wiki.

[Graham Banks]

Cupcake
ZetaDva
Heracles
Bibichess
Dabbaba
Marvin
Soldat
Reger
Clueless
Warrior

[Sedat Canbaz]

These are the engines that I have tried so far:
1. Gerbil 0.2 (stable)
2. TSCP 1.81d ja (stable)
3. Olivechess 0.2.7 (not stable, with memory leak)
4. Mint v2.3 (stable, but could not recognize pawn captures rook promote to knight)

Is there other stable engines you can recommend, uci or winboard, for windows?

I am developing a new engine with a goal to make it play positional moves (don't care the tactics), I am not interested on increasing its strength but instead try to lower it so that its move would look positional to a club player level.

This engine is based on Deuterium, but without nullmove, no reductions and prunings, only check extension, no egbb, but with hashing, evaluation is re-written. Changes in the eval so far:
1. piece values
2. pst
3. knight, bishop, and rook mobilities
4. passer
5. doubled, isolated, backward pawns
6. basic king shelter
7. rook in open file
8. rook in 7th rank
9. 2 bishops advantage
10. bonus for knight behind pawn
11. pawn and bishop colors scoring

The program is still strong, it can beat Gerbil but also loses for example, Mint and TSCP have difficulties beating it so far. I am trying to reduce its strength by adding more knowledge and computation time in the eval. I am holding implementation of null move and LMR. Perhaps implement null move with high reduction so that it will miss on some interesting positions.

Sample game vs me.

[pgn]
[Event "Computer Chess Game"]
[Site "INTEL-PC"]
[Date "2015.02.15"]
[Round "-"]
[White "Me"]
[Black "CDrill 1200"]
[Result "0-1"]
[TimeControl "300+1"]
[Annotator "1... +0.05"]

1. d4 Nf6 {+0.05/8 13} 2. c4 e6 {+0.01/8 12} 3. Nc3 d5 {+0.02/8 11} 4. Bg5
dxc4 {+0.05/8 10} 5. e4 Nc6 {+0.11/8 10} 6. Nf3 h6 {+0.10/8 9} 7. Bxf6 Qxf6
{+0.11/8 9} 8. Bxc4 a6 {+0.05/7 9} 9. O-O b5 {+0.22/8 8} 10. d5 Nb4
{+0.31/7 8} 11. Be2 exd5 {+0.24/7 8} 12. exd5 c6 {+0.31/7 8} 13. a3 Nxd5
{+0.32/8 7} 14. Nxd5 cxd5 {+0.34/8 7} 15. Qxd5 Rb8 {+0.28/7 7} 16. Rfe1 Be7
{+0.21/7 7} 17. Bd3 Bb7 {+0.33/7 7} 18. Rxe7+ Qxe7 {+1.78/8 6} 19. Qf5 Bc8
{+1.78/8 6} 20. Qf4 Rb7 {+1.71/7 6} 21. Re1 Be6 {+1.47/7 6} 22. Be4 Rb6
{+1.68/7 6} 23. Nd4 O-O {+1.65/7 6} 24. Bb1 Qd8 {+1.77/7 5} 25. h4 Bc4
{+1.88/7 5} 26. Nf5 Qf6 {+1.90/7 5} 27. Qe4 g6 {+2.14/8 5} 28. Nxh6+ Kg7
{+2.09/8 5} 29. Ng4 Qxb2 {+2.17/8 5} 30. h5 Re6 {+2.98/7 5} 31. h6+ Kh7
{+3.08/8 5} 32. Ne5 Qd2 {+3.18/7 4} 33. f4 Bd5 {+3.99/7 4}
{Black wins on time} 0-1
[/pgn]

Hello Ferdinand,

Several weeks ago,
I started testing many engines around 1500-2000 Elo under Arena GUI,
But later I noticed that almost all of them can not ponder, that's why I cancelled testing them...
And in my opinion,
Any chess engine should be able to ponder...it does not matter weak or strong...

Best,
Sedat

[hgm]

Seems to me it should be the choice of the engine author how he will use the CPU time that is granted to him. Pondering serves no other purpose than to make the engine stronger. So if the aim is to make a 'weak' engine that is beatable for humans, not having it use ponder time is one of the first things you would do.

[Sedat Canbaz]

Seems to me it should be the choice of the engine author how he will use the CPU time that is granted to him. Pondering serves no other purpose than to make the engine stronger. So if the aim is to make a 'weak' engine that is beatable for humans, not having it use ponder time is one of the first things you would do.

Thanks for your useful information, now I see...

Best,
Sedat

[Ferdy]

Testers have a very low tolerance level for unstable engines, so 99% of the engines you see on the CCRL list are stable. There are lots of engines below that level on the blitz list.

Yes I have seen both the CCRL and CEGT engine list, my first idea was to select the engine having more games , but it is also better to know from people who have actual experience.

[Ferdy]

This list is from memory. I have not used these engines in a while, and the GUI I used for them was primarily Arena 2.0.1. But I do not recall having problems with the following engines:

SamChess
Surprise 4.3b13
Roce 0.0390
Rocinante 2.0 64-bit (mcts)
Adamant 1.7
GChess IV 0.2.0
Kitteneitor 0.22.1
Bace 0.45
Cmcchess 2.5
MSCP 1.44

I believe that you can find links to all of these engines at the Computer Chess Wiki.

Thanks, I was able to try the first 4 engines so far and they are stable, I use winboard 4.6.2/4.7.3a/4.8.0b, There are times that 4.8.0b and 4.7.3a crashed, but 4.6.2 is stable and have no crashes. I will also try these engines in cutechess-cli 0.5.1 next. My engine is a little bit stronger than these 4 engines but it is all right since my goal is to be weaker with these engines.

I have 1 rule issue observed in Roce, it has ep bug.

[pgn]
[Event "Computer Chess Game"]
[Site "INTEL-PC"]
[Date "2015.02.16"]
[Round "39"]
[White "Roce 0.0390"]
[Black "CDrill 1200"]
[Result "0-1"]
[TimeControl "40/60"]
[Annotator "14. +0.37 14... +0.34"]

1. e4 c5 2. Nf3 e6 3. d4 cxd4 4. Nxd4 Nc6 5. Nb5 Nf6 6. N1c3 d6 7. Bf4 e5
8. Bg5 a6 9. Na3 b5 10. Bxf6 gxf6 11. Nd5 f5 12. c3 Bg7 13. exf5 Bxf5 14.
Be2 {+0.37/8 2.0} Ne7 {+0.34/6 2.2} 15. O-O {+0.39/9 1.9} Nxd5
{+0.62/6 2.2} 16. Qxd5 {+0.29/9 1.9} h5 {+0.59/6 2.2} 17. Rad1
{+0.64/8 1.8} Bf8 {+0.39/6 2.2} 18. f4 {+0.88/8 1.7} Be6 {+0.47/6 2.2} 19.
Qb7 {+0.81/8 1.7} Qc8 {+0.60/6 2.2} 20. Bf3 {+0.53/9 1.6} Qxb7
{+0.57/7 2.2} 21. Bxb7 {+0.64/9 1.6} Ra7 {+0.43/7 2.2} 22. Bc6+
{+0.43/9 1.5} Ke7 {+0.49/7 2.2} 23. fxe5 {+0.41/9 1.5} dxe5 {+0.80/7 1.1}
24. Ra1 {+0.36/8 1.4} f5 {+1.06/7 2.3} 25. Nc2 {+0.22/8 1.4} Kf6
{+1.06/7 1.4} 26. Kh1 {+0.22/8 1.3} Rc7 {+1.04/6 2.3} 27. Bf3 {+0.07/9 1.3}
Rd7 {+1.16/6 2.3} 28. Rfb1 {+0.04/8 1.2} Rd2 {+1.59/6 2.4} 29. Ne3
{-0.59/9 1.2} e4 {+1.84/7 1.8} 30. Bd1 {-0.68/9 1.2} f4 {+1.86/6 2.4} 31.
Nc2 {-0.93/9 1.1} e3 {+2.23/6 2.4} 32. Nd4 {-0.76/8 1.1} Bf5 {+2.11/7 2.4}
33. Nxf5 {-0.80/9 1.0} Kxf5 {+2.07/7 2.4} 34. Bf3 {-0.80/9 1.0} Rh6
{+2.12/7 1.8} 35. h3 {-0.66/8 1.0} b4 {+2.10/7 1.7} 36. Bxh5 {-0.57/9 1.0}
Rxh5 {+4.28/7 2.7} 37. g4+ {+1.10/9 0.9} fxg3 {+7.37/9 2.6}
{polyglot: resign (illegal engine move by white: f5g5)} 0-1
[/pgn]

[Ferdy]

Cupcake
ZetaDva
Heracles
Bibichess
Dabbaba
Marvin
Soldat
Reger
Clueless
Warrior

Thanks, good choice, I tried so far the first 3 both runs fine.