TOP 20:
# PLAYER : RATING ERROR POINTS PLAYED (%) 1 Stockfish 18 : 3875 10 4011.5 6500 61.7% 2 Reckless 0.10.0-dev-6abcff05 : 3855 13 1035.5 1900 54.5% 3 PlentyChess 7.0.55 : 3843 12 1646.0 3040 54.1% 4 Lc0 0.32.1 BT4-614750 4060m : 3842 20 283.0 480 59.0% 5 Obsidian 16.14 : 3833 12 1473.0 2660 55.4% 6 Alexandria 9.0 : 3820 13 971.0 1900 51.1% 7 Berserk 13-20250606 : 3810 11 2078.5 4160 50.0% 8 Integral v7dev-8bab : 3808 12 1110.5 2280 48.7% 9 Viridithas 19.0.0 : 3789 12 1439.5 3020 47.7% 10 Clover 9.1 : 3788 11 1613.5 3420 47.2% 11 Caissa 1.24 : 3783 11 3052.0 6440 47.4% 12 Pawnocchio 1.9.0 : 3781 13 1033.0 2280 45.3% 13 Quanticade 3.0 : 3778 13 763.0 1520 50.2% 14 Halogen 16.0 : 3777 11 1522.0 3420 44.5% 15 Tarnished 5.0 : 3774 13 1107.0 2290 48.3% 16 Horsie 1.1 : 3769 11 1975.0 4562 43.3% 17 Stormphrax 7.0 : 3757 12 1027.0 2280 45.0% 18 Uralochka 3.42a : 3752 13 697.5 1520 45.9% 19 Starzix 6.0 : 3747 12 888.5 1900 46.8% 20 RubiChess 20240817 : 3735 13 1289.0 3020 42.7%
Updates:
Tested Reckless 0.10.0-dev-6abcff05 and Integral v7dev-8bab.
Click here for the complete rating list:
The rating list – updated as of 04/04/2026 – 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…).
- 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).