The calculated ratings are not intended to be compared to Lichess, Elo, or Glicko-2 ratings. Ratings in different time-control groups are also not intended for comparison. While the player ratings from different years are much less biased than those on Lichess, they still do not have the same relational comparative accuracy as player ratings of the same month.

All rated antichess games ever played on Lichess are taken into account. Bots and all players marked as cheaters or sandbaggers prior to August 2024 have been removed and their games discarded. Cheaters and sandbaggers marked in August 2024 or later as well as those not yet identified are not excluded. No berserk correction has been made. All games are divided into four groups, based on time control. The 0+1 and ½+0 time controls are considered Ultrabullet. All other time controls are classified the same as on Lichess. The maximum rating deviation to include a player in the table is 40.0 for all time controls, except for Rapid, where the threshold is 45.0. This means that inactive players may not be shown in the tables during periods of low activity. Lichess ratings are not included in the calculation. Ratings for different time controls are calculated separately and do not affect each other.

To calculate the ratings, the Bayesian rating system as formulated by Vladica Andrejić is employed. The defaults are an initial rating of 1500, an initial rating deviation of 110, and a draw constant of 8. The last two constants have been optimized with the bounded Nelder–Mead method. The rating deviation decay is chosen in the same way as on Lichess. The update accuracy (rating period) is 1 second.

Main differences from the Lichess algorithm:

• Over the years, to calculate the ratings, Lichess has used different algorithms and different parameters. However, after adjusting the algorithm, the previous values have not been retrospectively updated.
• Lichess applies hard limits on the rating, its deviation, volatility, delta, etc.
• Due to the complexity of the recalculation procedure, Lichess does not properly recalculate the ratings of players who played against cheaters.

Note: most tournaments on Lichess are played in Arena format. In this format, in order to win the tournament, players are forced to “berserk” against low-rated opponents. This lowers their ratings and also indirectly affects those few players who do not berserk but are forced to play against opponents with artificially low ratings.

Among players who reached a rating deviation not exceeding the limit, ratings range from 941 to 2 276. The lowest rating deviation is 9.6. The Brier score is 0.301567.