Head-to-head Elo

How the head-to-head Elo is computed

A classic Elo rating over every recorded game between two Belgian players, replayed in date order. Everyone starts at 1500. Before a game the expected score of a player is 1 / (1 + 10^{(R_opponent − R_player) / 400}); afterwards the rating moves by K × (result − expected), so beating a stronger opponent earns more than beating a weaker one. Only games against other Belgians count, which is why this rating differs from the Elo on Board Game Arena.

BGA games (K = 8)

Every ranked two-player base game between two Belgian players. A game with other players at the table does not count, even when the two Belgians finish first and second. BGA does not tell which expansions were played, so a game with a score above 160 is assumed to use one and is skipped, as are unranked games. A game of an AMZ tournament (alphameeplezero.com) counts the same way.

Live championship (K = 24 / 32)

Swiss games of the Belgian Championship count with K = 24; the play-off games with K = 32.

BCOC and BCL duels (K = 28)

A duel in the online competitions counts once, as the share of games won (2–1 is scored 0.667). The individual BGA games of such a duel are not counted again.

Peak

The highest rating a player reached at any point in the replay. Wins and losses count every game and duel that moved the rating.