TOP 20:
# PLAYER : RATING ERROR POINTS PLAYED (%) 1 Stockfish 17.1 : 3859 16 4374.5 6930 63.1% 2 PlentyChess 7.0 : 3843 18 1122.5 1980 56.7% 3 Reckless 0.8 : 3835 18 1167.0 2280 51.2% 4 Obsidian 16.14 : 3835 17 1473.0 2660 55.4% 5 Clover 9.1 : 3799 18 971.5 1900 51.1% 6 Alexandria 8.0.0 : 3797 17 2530.0 4940 51.2% 7 Lc0 0.31.2 BT3-7464000 1650m : 3788 30 127.0 260 48.8% 8 Berserk 13 : 3783 16 5212.5 10320 50.5% 9 Integral 7.0 : 3779 17 1670.0 3420 48.8% 10 Caissa 1.22 : 3777 17 938.0 1900 49.4% 11 Viridithas 17.0.0 : 3754 20 627.0 1520 41.3% 12 Horsie 1.0 : 3753 18 609.0 1520 40.1% 13 RubiChess 20240817 : 3736 15 1145.0 2660 43.0% 14 Titan 1.1 : 3730 16 1041.5 2280 45.7% 15 KomodoDragon 1.0 : 3694 19 978.0 2660 36.8% 16 Seer 2.8.0 : 3689 17 869.5 2280 38.1% 17 Koivisto 9.0 : 3682 16 1742.0 3540 49.2% 18 Rebel 16.3 : 3674 23 209.0 770 27.1% 19 Fire 9.3 : 3642 19 600.0 1900 31.6% 20 Slowchess 2.8 : 3602 34 219.0 340 64.4%
Updates:
Added PlentyChess 7.0.
Click here for the complete rating list:
The rating list – updated as of 08/10/2025 – is calculated with Ordo and was obtained under the following assumptions.
- The Elo rating of Rebel 6 UCI (1994) is fixed at 2450 points, which serves as an “anchor” for all others. This score is the average value of the results obtained by the original version of the engine in various matches against human GMs in the early 90s, derived from various official or unofficial sources (Talkchess.com, Rebel13.nl, computerchessuk.com, various forums…).
- Compared to the previous version of the rating list, the second anchor, Fritz Brains in Bahrain (emulated from Deep Fritz 8), has been removed, as it distorted the true value of the engines too much.
- Several electronic chessboards have been added whose strength in terms of Elo obtained through matches with humans is fairly well known. In this way, the rating list should provide engine scores that are more easily comparable with human ones. The electronic chessboards were emulated with CB-Emu, and made to play against several UCI and Winboard engines of similar strength.
- The time per game was set to 40/120′ repeated, reparameterized to the processing speed of a Pentium 90. The execution speed of the latter was emulated, and through various benchmarks done in the past on real P90 machines, I tried to obtain a value as close as possible to reality. Consequently, on modern PCs the actual time per game was 40/125” or 40/130” (seconds) depending on the PC used for the test, comparable to other blitz tests found on the net. For some engines, such as Chess Titans, it was not possible to define a game time; for this reason, I have indicated the characteristics of the CPU on which it was tested.
- The opening suite consists of 190 different positions, repeated for each engine (each engine played the same opening both as white and black). For older engines, not equipped with a UCI or XBoard interface (such as the 1988 version of BattleChess), I manually reproduced the various moves suggested by the programs. Also for these engines, as for all the others, the playing time was reparameterized to the performance of a Pentium 90. For this reason, the games of these engines are few compared to the total, and based on random selections of the 190 openings. The opening suite can be downloaded here.
- All the chess engines used are freely available on the net, with the exception of commercial programs that I purchased years ago, and are limited to using only one CPU core.
- In the “Top 10”, I have not included past versions of Stockfish, nor engines derived from it (such as Shashchess). In the complete rating list, I have also included past versions of Stockfish for comparison.
- The main goal of this rating list, made for my exclusive enjoyment, was both to determine the playing level of modern engines compared to past ones, but also to evaluate the actual playing strength of many programs that I loved in my youth (the aforementioned Battlechess, for example).