Single Knockout Tournament Format
Single Knockout Tournament Format, also known as Single Elimination, is a format for pairing players to play games in tournaments.
In the first round, players are paired to play. Those players that lose are eliminated, knocked out of, the tournament. Those players that win, are promoted to the second round. This procedure is repeated till only a single player remains, that player is the tournament winner.
The number of rounds required is the ceiling of the log base 2 of the number of players in the tournament. (Example: 30 players necessitates 5 rounds of play because 2^5 == 32.) As a result, unless the number of players is equal to a power of 2, some players will play one more round than the others. Often the strongest players are not paired in the first round.
According to BGA,
- The probability that the best player wins is surprisingly small.
- There is no satisfactory way to produce an ordering for players other than the overall winner.
- maximize the probability that the best player will advance to the next round (goal focused on a single player)
- maximize the expected log-probability of game outcomes over all possible sets of pairings (goal focused on all players)
Note: that these two approaches may produce conflicting pairings. This is not surprising.