Keizer system
The Keizer system is an organizational method u. a. for chess tournaments . It was developed by the Dutchman J. H. Keizer in the late 1950s. A key feature is that not all players need to be present for all rounds. This is often the case at club championships when the rounds are not connected e.g. B. be held on a weekend, but spread over a longer period of time (often one round per week spread over n weeks).
Two much more well-known methods of tournament organization are the Swiss system and the all- round everyone against everyone . Both implicitly assume that the participants participate at least halfway reliably. With the Swiss system, for example, the next round can only be drawn when all the results of the last round have been determined.
Further features are simple rules for the draw, a complicated calculation of the table position (software required) and the determination of the table position based on the Keizer evaluation points instead of the game points (determined from wins and draws ).
The main features of the method
- The draw takes place directly before the start of the round based on the players present
- Pairings between the same players can optionally occur multiple times
- Each player has a score ("Keizer points"), which determines the table rank
- You play against partners with as similar standings as possible
- A win or a draw increases your own score significantly
- Absent players are also credited with points
The last point is basically an "absence draw", the increase in points is smaller than in a real, played draw.
Rules for the pairings
- The table status is sorted in descending order according to Keizer rating points (if they are equal, the rating is an additional criterion)
- The current table is traversed from top to bottom: of those present, the best placed against the second best placed, 3-4, etc.
- All participants present play; if the number is odd there is a bye
- The distribution of colors is "fair" - those who have had it less often get white
- If both had white the same number of times, the one behind in the table gets it
- Unlike z. B. With the Swiss system, the same color is allowed three times in a row
- In the case of odd players, the worst placed player present gets bye
Calculation of the Keizer evaluation points
- The table status is determined
- The players are assigned ranking points: 1st place the highest number, 2nd one point less, 3rd two points less, etc .; The number of points for the 1st place is chosen so that the first gets about three times the last (e.g. with 6 participants 7 points for the 1st, 6 for the 2nd etc. up to 2 points for the 6th)
- The ranking points are now added up depending on the results of the game: for every victory the current ranking points of the opponent, for every draw half of the ranking points of the opponent, in the case of a defeat 0.
- Bonuses are also added up: rounds not played are counted as a draw against yourself, you get half of your own ranking points (usually reduced by a predetermined factor to make sitting out less attractive).
- The calculation runs iteratively through all rounds: the first table status is formed using the rating, then the game results of the first round are evaluated and added up. This results in a new table status, based on which the ranking points are reassigned. Then the first two rounds are reevaluated, results in a new table status, etc.