This is the direct elimination system. A player who loses a game leaves
the tournament. The tournament continues until one single player stay
and that player is the winner. For a tournament with 2n players,
n rounds will be necessary.
Each player meets every other one.
Comes from the KO system. But there is no elimination. Pairing is made
between players having the same number of wins.
To work correctly, a minimum of n rounds is required for 2n
players. This is sufficient to clearly determine a winner. However, in
order to be able to set a satisfying placement for all players, n+1 or
n+2 rounds are recommended.
For final placement a tiebreak method is usually
See also the rules for inner-group pairing.
If there are more players in a tournament than the number of rounds can
handle (to determine a clear winner), then separating players in categories
can be considered.
If there are more players in a category than the number of rounds can
handle, then "accelerated" pairings can be considered. Accelerated
pairing is popular in chess tournaments. With such a system, it is
possible to handle a 2n+1 players tournament with only n rounds.
If the initial seeding is reliable, only one player will achieve the tournament
with n wins and be therefore a clear winner of the tournament.
It is the most popular system in European Go tournaments
See a description of Mac-Mahon System