There are a few common tournament bracket formats, we will briefly go over them here.
Single Elimination is a simple format where once a player loses, they are eliminated from the tournament. This format is popular for team competitions and informal tournaments since it is very fast to run, the total number of matches player is equal to the number of players - 1.
The basic flow is:
- All players are assigned a person to face
- Players who win advance and face other players who win. Players who lose are eliminated from the tournament
- Repeat until a single player remains. They are the winner of the tournament
Double Elimination is a format where a player must lose twice to get eliminated from the tournament. This is a popular format for 1v1 competitions because it determines the top 4 without having any tiebreaker rounds, and everyone has a second chance to play more tournament matches. The downside is it almost doubles the number of matches needed compared to Single Elimination, and delays are common because matches need to wait for other matches to complete.
The basic flow is:
- All players start in Winners Bracket, like in a Single Elimination bracket
- Players who lose in Winners Bracket get placed in Losers Bracket
- Where they get placed in Losers Bracket depends on how many matches they won in Winners Bracket
- Players who lose in Losers Bracket are eliminated
- The two final players (the winner of Winners Bracket and the winner of Losers Bracket) compete in Grand Finals.
- In Grand Finals, if the player from Losers Bracket wins, then the two players must play another match (this is called a Bracket Reset). This is because both players will have the same tournament standing at this point (one loss each), and need to play again to determine who's the winner.
For larger tournaments (like most majors), it makes sense to split the players up into groups of players called pools. Each pool works like a smaller double elimination bracket, except instead of playing until a winner is decided, the top X players advance to the next stage. The number of players that advance depends on the tournament and can vary from 1 to 4 players.
The players that advance will populate a double elimination bracket, with players staying in the same bracket as when they advanced from pools (ex: advancing from pools in Losers Bracket means you will begin the next stage in Losers Bracket).
Pools are used so more matches can be played concurrently, as there will be less bottlenecks in later rounds of the tournament, and players that advance out of pools can know when their next match will be played instead of waiting for unknown amounts of time for brackets to catch up to them.
The number of player slots in a Single or Double Elimination tournaments needs to be a power of 2 (ex: 8, 16, 32, 64, etc.) in order to function fairly. Obviously that doesn't mean you need that exact number of players to run single/double elimination tournaments; the slots remaining are filled with empty spots called Byes and are spread evenly over the entire bracket.
Seeding is the act of deciding player's starting positions in a bracket/pool. There are two common types of seeding - Skill and Regional. Both factors are considered when seeding brackets.
- Skill Seeding
- The goal here is to spread the higher skilled players (as decided by the Tournament Organizers or some ranking system) as far apart in the bracket as possible. This serves two purposes:
- "Save" matches between higher skill players for later in the tournament in order to concentrate spectator attention on matches expected to be exciting to watch.
- The difficulty of advancing out of any pool is reasonably fair. (ie no pools with lots of high level players or no pools with zero high level players)
- Region Seeding
- The goal with regional seeding is to spread players apart based on where they live to prevent players from the same region from meeting early in the bracket.
- Presumably, players from the same region have faced each other before, and would rather face new players.
Round Robin is simple; everyone faces everyone else and the player with the most wins is the winner. This format is used when there are few players since the amount of matches to run Round Robin Tournaments quickly grows to an impractical size. This format is great when everyone wants to face everyone else in a structured way.
See also: Round Robin Tournament on Wikipedia
The Swiss System is a twist on Round Robin that tries to match players that have the same score every round.
- Decide the number of rounds to be played.
- This is usually the same number of rounds needed to run a Single Elimination Tournament with the same number of players.
- First round, players are paired at random or through seeding
- In subsequent rounds, players face other players with the same win/loss score
- If there are an odd number of players, then the odd player out is given a Bye (counts as a win for the round)
- Players may not face the same opponent twice, and may only be given one Bye
- Repeat until the desired number of rounds are played
- The player with the best score is the winner
See also: Swiss System Tournament on Wikipedia