CCRL Blitz
Downloads and Statistics
May 1, 2021
Testing summary:
Total: 2'515'858 games
played by 2'996 programs

White wins: 966'865 (38.4%)
Black wins: 774'272 (30.8%)
Draws: 774'721 (30.8%)
White score: 53.8%



CCRL means "Computer Chess Rating Lists". We are a club of people inspired by watching computers play chess. We want to compare the strength of different chess programs, and we want to share our findings with others. We are achieving this by running thousands of games between chess programs, collecting the games into a single database, and then computing and publishing a rating list.

** Please note that our role as a group is not to decide on the originality of engines as we have neither the legal or technical expertise. Viewers of the website must make their own judgements. Inclusion or non-inclusion of an engine should not be interpreted as a statement by us of the status of that engine **

CCRL was formed in December 2005. Initially we only did 40/15 testing, but later more members joined and we are now doing 40/2 and FRC testing as well. We now have members from several countries, with diverse ideas, but united by single passion.

CCRL Blitz

2'+1" is our fast "blitz" time control as from January 2020, with previous games played at 40/2 repeating time control.

Our members are free to choose any engines they like to test, as long as the testing is done under conditions stated below.

CCRL Blitz Testing Conditions

Time Control: As from January 2020, the blitz list is transitioning from a 40 moves in 2 minutes repeating time control to game in 2 minutes plus 1 second increment, 2'+1", on an Intel i7-4770k. Over time the list will reach a point where new engines and engine versions will have played at the new time control, and old versions and engines at the old repeating time control, with some engines having played both. At that point we can make a decision whether to leave things as they are, or move the games at the new time control to a brand new list and archive the old one.

We use Stockfish 10 as a benchmark to determine the equivalent time control for a particular machine.

Endgame tablebases: 4, 5 or 6 piece tablebases.

Pondering: OFF.

Tournament format: Any format of tester's choice: Match, Round-robin, Gauntlet, Swiss, etc.

Hash size: Should be set to the same value of either 128 or 256 MB for all engines in a match or tourney. There are two exeptions: 1) Engines using 4 CPUs should have up to four times the hash size, compared to single-CPU engines in the same tourney. 2) Smaller hash size can be used if an engine has problems with particular hash size, or if it does not allow to configure hash size.

EGTB hash: 32 MB or 64MB.

Tournament Interface: Any. Examples: Winboard, Arena, Shredder, Chessbase, Chess Partner, Cutechess, ChessGUI.

Opening book: Any generic. Examples: remis.ctg, draw.ctg, 5moves.ctg, perfect.ctg etc. Book line length has to be limited to 12 moves per side maximum. The same book should be used for all engines in the same match or tournament.

Engines with their own books should have them disabled (deleted or switched off in parameters). Engines which can't disable their own book can't participate in CCRL testing.

Book learning: Off for all engines.

Position learning: Off for all engines.

Created in 2005-2013 by CCRL team
Last games added on May 1, 2021