Ranking

Casual matches are for practice and never move your standing. The official ranking comes from a weekly tournament per game and variant. The cards below are the whole system at a glance; the sections after them fill in the details.

Friendly vs ranked

Any match you start by hand is friendly. Friendly matches do not change scoring or ranking. They are for trying ideas, debugging a bot, and watching replays. The official ranking is set only by the weekly cup described below.

A ranking is an ordinal position for one game and variant: rank 1 is the best bot, rank 2 the next, and so on. Each variant has its own ladder, so a bot can sit at different ranks across a game's variants.

The weekly World Cup

Once a week, each game and variant runs a World Cup. The entrants are every user's one ranked bot for that game (the bot you published and marked use for rankings), plus all the built-in house bots. The cup is seeded by current Elo rating. Elo is no longer a public score; it exists only to seed the bracket so stronger bots meet later.

When the cup finishes, its final standings become the ladder for that game and variant until the next week.

How the cup shape depends on the field

The cup grows with the number of competing bots N, and it always ends in a home and away double round-robin among the top C = min(N, 8). Every stage is round-robin. There is no single-elimination knockout.

• N up to 8. One stage. A double round-robin where everyone plays everyone else twice, once at home and once away.
• 8 to 32. A group stage first (groups of about four, single round-robin, three points for a win) ranks the whole field. The top 8 go on to the championship double round-robin. The rest keep their group rank as ranks 9 and down.
• Over 32. Qualification group rounds cut the field to 32 first, then the 8 to 32 path above runs.

Why home and away

In most games the bot that moves first (seat 0) has a small edge. Playing each pairing twice, with the seats swapped, cancels that edge. The away leg is also the rematch: if the two legs split, the standings break the tie on the rules below rather than on who happened to start.

Standings and tiebreakers

Within a stage, bots are ordered by, in order:

• more points;
• then more efficient play: less total fuel spent, then fewer moves, then fewer turns;
• then the better seed.

New bots between cups

You do not have to wait a week to get a rank. When a new ranked bot arrives between cups, it is placed by a binary search: it plays the bot in the middle of the current ladder, home and away, and the result narrows the search up or down until its slot is found. These mid-week slots are marked provisional. They sit after the bots placed by the weekly cup, and the next cup re-runs the whole field and replaces them.

One ranked bot per game

You field one ranked bot per game. That single bot represents you across all of that game's variants. You can keep other bots for friendly play, but only the one you mark for rankings enters the cup.

Your score across games

A player's overall standing starts from their best game. In a ladder of N bots, rank r is worth the percentile (N - r) / (N - 1): rank 1 scores 1, last place scores 0, and your standing in a game is your best variant ladder in it. Players are ordered by their best game; ties fall to the second-best game, then the third, and so on. There is no averaging, so entering another game can never lower your rank. When two players' scoresheets carry the same values, the tie is settled game against game, walking the games in the order of the games page. Retired games' frozen ladders and house bots are left out.

Follow the cups, live brackets, and upcoming start times on the tournaments page. See where everyone stands on the player leaderboard.