After submitting their decks, registered participants are randomly divided into groups of 6 to 10 players depending on the number of participants:
< 16 participants: unique Final Group
16-24 participants: 2 groups (and a Final Group of 8)
25-33 participants: 3 groups (and a Final Group of 9)
34-44 participants: 4 groups (and a Final Group of 8)
45-55 participants: 5 groups (and a Final Group of 10)
56-70 participants: 7 groups
71-80 participants: 8 groups
81-90 participants: 9 groups
91-100 participants: 10 groups
101-120 participants: 12 groups
121-140 participants: 14 groups
141-160 participants: 16 groups (then two groups of 8, leading to a Final Group of 8)
161-180 participants: 18 groups (then two groups of 9, leading to a Final Group of 10)
Each group battles it out according to the Format Rules below. The winner (or the top 2) of each group makes it to the next Stage. In the case of a tie, head-to-head is the first tiebreaker. If still tied, results against the best-placed player are considered, and so on. If still tied, the winner will be chosen randomly based on their position in the groups sheet (higher position wins the tie).
In the next Stage, new groups are extracted if necessary. Promotion to the Final Group is explained above.
The first non-basic land card (as per submission) of each deck in the Top 4 of the Final Group will be banned for use in subsequent Rounds. When 50 cards have been banned, new bans replace older ones.
An unbanned card that receives a second ban is banned for the following 25 Rounds and it does not count towards the 50-card limit. It will be unbanned at the end of the 25th Round if at least half of the participants vote for its unbanning.
Each time a card is banned after the second time, it is banned for the following 50 rounds, and it does not count towards the 50-card limit. It will be unbanned after the 50th round if at least half of the participants vote for it.
Once the groups have been determined, players submit their results on the Report Results page according to the following rules:
A deck only consists of three cards. No other card is owned by the players besides the ones submitted. Note that Dungeons, Stickers, and Attractions are all considered cards for the purposes of this tournament, so they cannot be added to the game.
Each player starts with all three cards in their hand: mulligans are not permitted.
The game is played with complete information i.e. hands, libraries, and all secret information is revealed.
Players draw cards but do not lose the game for being unable to draw a card.
Random effects end in the result most beneficial to the opponent of the owner of the card generating the effect; this includes things such as shuffling or flipping a card.
Players start with 20 life points. If the match does not end, it is considered a draw.
For each win, a player gets 3 points, for each drawn game 1 point, and for each loss no points.
Each group consists of a double round-robin where each player plays each other player both on the play and on the draw.
Timmy: Black Lotus, Black Lotus, Visara the Dreadful
Johnny: Black Lotus, Treasure Hunter, Aura of Silence
Spike: Golgari Rot Farm, Treetop Village, Putrefy
Timmy vs. Johnny: If Timmy begins he can play Visara first turn and win the race against Johnny's Treasure Hunter or just destroy the Treasure Hunter. If Johnny begins, he can play Lotus, Hunter, Lotus and Aura and Timmy can not play his Lotuses and Johnny just beats him with the Hunter. The Matchup is 3-3.
Timmy vs. Spike: In either scenario, Timmy can not deal lethal damage before Spike has enough mana to cast Putrefy and destroy Visara. Spike will beat down Timmy with the Village. The Matchup is 6-0 for Spike.
Spike vs. Johnny: Aura of Silence does not affect Spike at all. As such, Spike can just destroy the Hunter with Putrefy and win with Treetop Village. Spike wins this Matchup 6–0.
This example and the format rules were shamefully copy-pasted from the MtG Wiki.
Add the following to the Comprehensive Rules:
100.2e In a 3CB game, decks must have exactly 3 cards.
100.4e In a 3CB game, players cannot own any card besides the ones in their deck.
103.1d In a 3CB game, a match always consists of two games. Choose a different first player for each game in the match.
103.4e The initial hand size for a 3CB game is 3 and mulligans are not permitted.
104.3l Rule 104.3c does not apply to 3CB games.
104.4j A 3CB game is a draw if the same identical game state is repeated 3 times in different turns.
400.2a In a 3CB game, all zones are considered Public Zones.
906. 3CB
906.1 In a 3CB game, all random effects including shuffling are instead determined by the opponent of the source's owner that generates the effect.
906.2 3CB games are not actually played by the players. Instead, the result is determined based on the assumption of perfect play:
906.2a If a player would take an action take that would lead to them losing the game, they try to take a different action. If no such action is available, they lose the game.
906.2b If a player would take an action take that would lead to them drawing the game, they try to take a different action that does not lead to a loss. If no such action is available, they draw the game.
Decks containing cards in the Dynamic Banlist for the Round score 0 against all opponents.
A submission deadline for each Round will be communicated with at least 6 days' notice. We expect to have rounds roughly every 10 days. Players can submit using the Submit Deck page.
Players register for each Round separately using the Submit Deck tab. Multiple submissions are not allowed. You have an option to leave your email address to be notified about the publication of the Pairings, and the opening of the next round.
The organizer must submit their deck before seeing any other player's submission.
Once the Pairings have been published for the Round, the organizer will compute the results. If you disagree with a published result, you may comment on the spreadsheet, on discord, or on reddit.
After each Round, the Leaderboard will be updated according to the following rules:
Winning a group gives 5 points, excluding the Final Group. These points are awarded to both players in the case of ties that require a random winner.
Qualifying to the Final Round by being second in a group gives 3 points. These points are awarded to both players in the case of ties that require a random winner.
Qualifying to the Final Round by being third or fourth in a group gives 1 point. These points are awarded to both players in the case of ties that require a random winner.
If multiple players submit the exact same deck, and some make the finals from a group while others don't due to the random tie breaker, these players all evenly split the points scored in the finals by those who made it.
The Top 4 of the Final Group receive the following bonus points:
15 points
9 points
5 points
2 points
These points are divided among tied players in the case of ties that require a random winner.