Introduction

CCRL

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 40/15

40/15 is the main "medium" time control we use. It allows us to obtain high quality games while still collecting enough games for meaningful statistics. First CCRL 40/15 game was played on December 19, 2005.

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

CCRL 40/15 Testing Conditions

Time Control: Equivalent to 40 moves in 15 minutes on an Intel i7-4770k. We use Stockfish 10 as a benchmark to determine the equivalent time control for particular machine.

We use repeating time control. It means that, say, in 40/15 the engines have 15 minutes for the first 40 moves. Then they get another 15 minutes for the next 40 moves, and so on.

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 256 or 512 MB for all engines in a match or tourney. There are two exeptions: 1) Engines using 4 CPUs should have up to four times 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: 32MB 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 40/15 testing.

Book learning: Off for all engines.

Position learning: Off for all engines.