The 2025 Atomic World Championship Rules

The 2025 Lichess Atomic Chess World Championship

1. General Information

The 2025 Atomic Chess World Championship (AWC 2025) will be open for registration from 15 July 2025 at 00:00 UTC to 15 August 2025 at 00:00 UTC via: https://awc.chessvariants.training (or another method to be determined)

The games will be played at https://lichess.org. Matches will start at 00:00 UTC on 3 September 2025 and continue until a participant becomes the new Atomic World Champion.

The Tournament Director (TD) is HowlinD. The assistant Tournament Director is Puredication.

The following rules are written to be as complete and succinct as possible. Any situation not covered within the rules will be settled by the Tournament Director.

2. Format of the Championship

2.1 The format for the 2025 Lichess Atomic Chess World Championship will be a single elimination knockout format, with a cut to a double elimination knockout top 16.
The number of entrants will be 16, 32, 64, or a greater power of 2. If the number of entrants is a bit greater than those amounts, then the first round will pair the lowest seeded players until the new total is a power of 2.
If a player loses a match prior to reaching the top 16, they are eliminated. After the cut to the top 16, the tournament becomes a double-elimination knockout, and ends when there is only one player remaining that hasn’t been defeated twice.

2.2 The tournament is seeded to ensure that the strongest players get matched later in the tournament.

2.3 Players withdrawing before the start of the tournament receive no penalty. If a player withdraws from the tournament after it has started, they may receive a 1 year ban, depending on the reason provided. If a player influences the results of too many matches by helping other players, they may receive a 1 year ban.

3. Eligibility of Entrants

3.1 A player must understand that this event requires a time commitment from them. A player should not register if they don’t have enough time to schedule, prepare, and play.

3.2 A player must be able to play rated games on Lichess. If a player loses the ability to play rated games on Lichess without it being restored before their next match, they will be forfeited.

3.3 A player must be able to communicate with another player via private messaging on Lichess. If a player is muted, they may use another account to communicate, and must notify the TD of that account’s name. If a player is blocking their next opponent, they must unblock them to schedule and play their match.

3.4 A player must apply to join only once and only using their “primary” account. If a player tries to register on an account with few games, they may be asked to provide the name of one of their other account(s), or past account(s) to the TD. Without additional information, accounts with a rating that isn’t reflected by their amount of games played may not be allowed to register. Chess.com players may be allowed to register at the TD’s discretion.

3.5 A player must have played at least 500 rated atomic chess games on Lichess or Chess.com. The account applying for registration must be at least 4 months old at the start of registration, or the player must have mentioned a previous account or a chess.com account that met this criteria to the TD following registration.

3.6 A player must have played at least 200 rated atomic games over a period of 1 year before the start of registration on the account used to register to the AWC, or on a Chess.com account mentioned to the TD following registration. Limited exceptions may be granted to established or titled players.

3.7 A player must have reached a peak rating of 1700+ on Lichess, or reached a peak rating of 2000+ on a Chess.com account mentioned to the TD following registration.

3.8 A player must not have been marked for use of an engine over a period of 2 years before the start of registration, on both Lichess and Chess.com.

3.9 A player must not have been marked by multiple rated “Cheat detected” games over a period of 2 years before the start of registration.

3.10 A player must not be on the lifetime AWC banlist, which includes all players who have been disqualified from previous AWCs for cheating, or disturbing the tournament.

AnthonyPower (2018 AWC incident, lifetime ban)
Timofey (2019 AWC incident, lifetime ban)
Gagarin-Vadim (2020 AWC incident, lifetime ban)
Gannet (personal admission of cheating, lifetime ban)
Derekbum (2022 AWC incident, lifetime ban)
Bobogokou32 (2023 AWC incident, lifetime ban)
Advocaat (2023 AWC incident, lifetime ban)
Atomic_en_Cuba (2023 AWC incident, lifetime ban)
ATOZ47 (2023 AWC disturbance, lifetime ban)
jasos12 (2024 AWC incident, lifetime ban)
(2025 placeholder)

4. Match Negotiations

4.1 Players may begin negotiating a match time as soon as their next pairing is known.

4.2 Each player is required to send an offer proposing (at least) three separate times on three separate days, at which they are available to play their match. All times should be communicated with the UTC (Coordinated Universal Time) format.

4.3 If a player fails to send their time offer in a timely manner, they must accept one of their opponent’s proposed times.

4.4 A player should respond to a match offer by either accepting an offer or by making a different offer, preferably within 24 hours.

4.5 If a player is excessively or repeatedly late for scheduled matches they may be forfeited.

4.6 If both players propose 3 time offers but no agreement is made before the deadline, then a TD will determine who is at fault by asking for a screenshot of the conversation between the two players. If a player is at fault then their opponent will decide the match time. If no player is at fault the match arbiter will assign a match time. If both players are at fault, in most cases, the higher-seeded player will be advanced.

5. Match Regulations

5.1 A match consists of 10 rated atomic games with a 3+1 time control, with alternating colours. It is common etiquette in atomic to equalize colours during a match, and it is strongly encouraged to do so.

5.2 The first player to reach 5.5 points in the first 10 games is the winner. The match can be stopped once a player has won, or continue for all 10 games.

5.3 If the first 10 games end with an equal score of 5-5, 2 tiebreaker games will be played using the same rules as the match. If a player reaches 6.5 points, they win the match. If the first set of tiebreaker games ends with an equal score of 6-6, 2 additional tiebreaker games are played. If a player reaches 7.5 points, they win the match.

5.4 If the second set of tiebreaker games ends with an equal score of 7-7, a final Armageddon game is played, which decides the match. A draw is considered a win for black. There is no increment, and black starts with 3 minutes. Both players must message an available TD, or a non-TD player that they both trust, with the lowest time offer they are willing to play as White. The lowest possible time that is available is 1/2+0, and the time offered must be a multiple of 15 seconds. If the offers are identical, the higher seeded player will play White. To set up the game, one player will challenge the other to a rated game of 1/2+0 atomic, and then both players must hit the “add 15 seconds” (a blue “+” sign next to the timer) until they get the appropriate times on the clock, before making the first move.
Note: Both players must make sure to have selected “Always” to the “Give more time” option in the Lichess settings (https://lichess.org/account/preferences/chess-clock) to be able to “add 15 seconds”, and to either play on PC or on the Lichess mobile app.
Example: Player A bids 2:15 and Player B bids 2:30, Player A wins the bid and will play White. The game is started by sending a 1/2+0 rated challenge, accepting it, and then with Black hitting the “add 15 seconds” button 7 times to get White to 2:15 minutes, and White hitting the “add 15 seconds” button 10 times to get Black to 3 minutes.

5.5 Each player is allowed one break of up to 10 minutes in between games of the same match. If the player that requested the break does not return after 10 minutes, the next game is awarded to the player that did not request the break. If the player that requested the break has not returned after 10 more minutes (20 minutes in total), the match is awarded to the player that did not request the break. If a player wants to leave the match and resume it later, the opponent is free to refuse, and can claim the win. If they agree to resume later but fail to reschedule, the player who left the initial match is forfeited.

5.6 During the match, outside of a break, the next game must begin within one minute of the previous game ending.

5.7 Players cannot claim victory if their opponent has disconnected and still has time on their clock. If a victory is claimed this way, the game is forfeited to the player that did not claim victory. Do not click the Lichess “claim victory” button in these scenarios.

5.8 If an automated system process on Lichess forfeits a player during a game for using external assistance (“Cheat detected”), this player forfeits the match.

5.9 After a match ends, at least one player must report the results in the “Rounds and Results” forum thread, by mentioning the two players, the score, and linking the first game.

5.10 If the opponent does not appear within 20 minutes of the agreed upon match time, the match is forfeited to the player waiting for the match. To prove this, the player waiting for the match needs to message a TD once, and then once more 20 minutes later.

6. Accusations of Cheating

6.1 Accusations of cheating must be sent to Lichess moderators using the report function. Additionally, it is recommended to notify the TD privately.

6.2 Accusations of cheating must never be made publicly. If a public accusation is made by either a player or spectator, the accusing player/spectator may be forfeited and issued a 1 year ban for disrupting the tournament.

7. Seeding and Alternative Rating Systems

7.1 Seeding Rating is calculated with the following formula:
(Base Rating + Performance Rating)/2 = Seeding Rating

A player’s Base Rating is their peak established rating in atomic chess reached on Lichess between over a period of 1 year before the start of registration.

A player’s Performance Rating is their highest tournament performance from Lichess-created tournaments (with at least 5 different opponents faced) over a period of 1 year before the start of registration, adjusted by number of games played and the time control of the tournament (see 7.2).
Here are some exceptions for which the seeding formula is modified:
In some cases, the TD will manually adjust a player’s seeding rating to better reflect that player’s abilities. If that happens, an asterisk will be added next to that player’s name.

Past AWC winners (2005 and post-2016 editions only) automatically receive a 2500 base rating, and 50 base rating points per additional AWC won.
A top-2 finish grants a 2400 base rating, and 25 base rating points per additional top-2.
A top-8 finish grants a 2300 base rating, and 15 base rating points per additional top-8.

7.2. Performance rating is calculated with the following formula:
(Tournament Performance + TC modifier + Games modifier) = Performance Rating

The Tournament Performance can be found on any lichess tournament page. Only Lichess-created tournaments are taken into account.

The TC modifier is the amount of points deducted based on the time control of the tournament played.
Tournaments in faster TCs than 1+0 will not count for Performance Rating.
1+0 tournaments will have a TC modifier of (-60).
2+0 and 1+1 tournaments will have a TC modifier of (-30).
3+0, 2+1, 3+1, 3+2, and 5+0 tournaments will have a TC modifier of 0.

The Games modifier is the amount of points deducted or added based on the number of games played in the tournament.
10 games played: (-60) Games modifier
12 games played: (-40) Games modifier
14 games played: (-20) Games modifier
16 games played: 0 Games modifier
18 games played: +20 Games modifier
Every 2 games played over 18 games will add +5 to the Games modifier (to a maximum of +100 Games modifier for 50 games played).
Every 2 games played over 50 games will add +2 to the Games modifier (to a maximum of +150 Games modifier for 100 games played).

8. Impartiality Guidelines

8.1 In case the Tournament Director is participating in the tournament, any matter directly involving the TD as a participant will be decided by a neutral party arbiter.

8.2 The Tournament Staff must be impartial and fairly treat all matters and players alike.