Swiss system

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The Swiss system is a form of tournament that is particularly widespread in the game of chess , but is in principle possible in all tournaments with games between two people or teams. This system is particularly useful if, due to the large number of participants, for reasons of time alone, it is not possible for everyone to play against everyone (as would be the case in a round-robin tournament ).

history

In 1895, the Swiss teacher Julius Müller developed a competition format or pairing system for sporting events, known as the Swiss system .

“The Swiss system invented the Swiss - that's why it's called that. Strictly speaking, it was only a Swiss man - Dr. Julius Muller. The system could therefore also be called the Müller system. "

- André Schulz

The basic idea

The Swiss system can best be described as a special form of round-robin tournament. The first round is placed or drawn; after each round the intermediate result is determined, and in the following rounds the leader always plays against the runner-up, the third against the fourth and so on.

It is excluded that two players meet twice. The pairings are therefore determined before each round as follows:

  • the leader plays against the highest ranked player he has not yet played against,
  • the leader of the remaining players plays against the top ranked player he has not yet played against, etc.

If several participants have the same number of points, a ranking must be established among the participants with the same number of points by drawing a lot or by setting.

Exact design

If more than two participants have the same number of points after a round, there are several systems that determine the pairings to be set up for the next round.

  • First of all, secondary criteria can be used, such as the quantitative equalization of the white and black parts of a player in order to rule out individual possibilities.
  • Loosing the pairings: This leaves a lot of space for chance, which can easily lead to distortions of the result.
  • Pairing in the ranking list of directly neighboring participants: The first of the ranking list is set against the second, the third against the fourth, etc. If the nominally stronger participant wins in each pairing, after eight rounds and 512 participants, numbers 1 and 257 of the starting field together lead, without number 257 having played against a nominally stronger participant. This method ensures interesting pairings in the first few rounds at the expense of the accuracy of the final table.
  • Pairing via halving: Participants with the same number of points are divided into two halves, for example according to their skill level / rating. Then the first of the upper half is preferably paired against the first of the lower half and so on. After eight rounds, numbers 1 and 2 of the starting field lead in the example without having played against each other. This system promotes a separation of good and bad players and neglects the precise determination of the ranking of the good players among one another.
  • The so-called accelerated system lies between these two variants; instead of halves, quarters are formed, and the first is paired with the second, the third with the fourth quarter.

rating

In contrast to the knockout system, a defeat does not mean you are eliminated from the tournament. The Swiss system delivers accurate results in the upper ranks (1st place, 2nd place), as well as in the lowest (last, penultimate). However, the ranking in the midfield is highly random.

In order to determine a clear winner, you need at least as many rounds according to the Swiss system as according to the knockout system . However, if the front runner loses a game or multiple draws are played, then more rounds are needed to determine a winner. The more rounds are played, the more precise the continuous sequence becomes.

The importance of the last rounds for the placement at the end is very high, many decisions are usually no longer made in a direct comparison, but in an indirect duel.

If n-1 (even n) or n (odd n) rounds are played in a tournament with n participants , the Swiss system goes over to a round-robin tournament everyone versus everyone : the more rounds are played, the theoretically more precise the continuous sequence . However, it is generally only guaranteed for the first round that a new round can be drawn without two players meeting each other twice.

It is often criticized that participants who miss points at the beginning of the tournament are preferred under certain constellations. A participant (X) who wins every game always has to compete against the strongest on the field, while another (Y), who only achieved a draw in the first round, meets supposedly weaker opponents in the following rounds. If both players win all the following rounds and meet in the last round, then Y can secure the tournament victory by defeating X without ever having had opponents as strong as X. It is sometimes assumed that X consciously accepts the loss of points in the first round for this reason. Such a strategy is sarcastically referred to as the “Swiss Gambit”, based on gambit openings in chess, in which a player sacrifices a pawn in order to gain a strategic advantage in the game.

application

This form of tournament can be found especially at

  • Chess tournaments: In the game of chess, ties are very common, so a knockout tournament is very problematic - every single game round would have to be played over the distance of several games (and even then there is no need to determine a winner). On top of that, tournaments should not only determine a winner, but often also remain interesting for other participants in the game for placements. However, since a chess game only has three possible outcomes (win, draw or defeat), equal points in tournaments according to the Swiss system are inevitable; a continuous ranking is only achieved using fine evaluation methods such as the Buchholz evaluation .
  • Team tournaments in bridge : After each round, the teams are sorted according to the victory points they have earned . Since the results of the individual fights are very different, measured in VPs, there is usually a continuous ranking after each round, ex aequo placements are rare.
  • Pétanque tournaments: tournaments in the boule sport pétanque are held in the Swiss system, among other things. There are tournaments in which, as in chess, Buchholz points and Fein-Buchholz points are used for the fine scoring. In other tournaments, victories and point differences are used for the fine scoring instead of or in addition to the Buchholz scoring.
  • Badminton tournaments : If there are high numbers of participants, the Swiss system is also used in this sport
  • Table tennis tournaments
  • Table football tournaments : Usually Swiss system with Buchholz and Fein-Buchholz points
  • Counter-Strike: e.g. B. ESL One Cologne 2016 (Qualifier) (also with Buchholz points )

Modifications

With the Swiss system, the same participants cannot meet again. The similar Danish system differs from the Swiss system in that the same pairings can occur several times: In each round, the first against the second, the third against the fourth and so on.

Bridge tournaments usually start with the Swiss system, so that the same teams cannot clash for a long period of time, but in the final phase the Danish system is used for one or two rounds, so that, for example, the two top teams can fight for can win the victory directly among each other, even if they have played against each other before.

A special form of the Swiss system is the Mac-Mahon system , which is often used in Go tournaments. Here the players do not start with zero points, but with the (generally different) number of points that corresponds to their classification in Kyu or Dan grades.

Use in chess

The Swiss system is used in chess and similar competitions to determine pairings. It was used for the first time at a chess tournament in Zurich on June 15, 1895.

The Swiss system is mainly used in tournaments with a large field of participants, because time constraints mean that not everyone can play against everyone. The first round is drawn according to the previously sorted field of participants, with the FIDE system playing the upper half against the lower half. From the second round onwards, the current table is used in such a way that players who have the same number of points always meet if possible, without two players being allowed to meet more than once in the course of the tournament. If there is no opponent with the same number of points for a player, he is assigned to the next group. In addition, care is taken to ensure that as many players as possible play a balanced number of black and white games. Within a point group, the players are also sorted according to the seeding list, ie according to skill level, and the players from the upper half meet the players from the lower half if possible.

With this system there are interesting games in every round, since almost every game is a direct placement battle between two similarly strong players - for this reason it is not necessary for a meaningful table to have everyone play against everyone. However, the Swiss system has the disadvantage of only differentiating well at the top and bottom of the table. In the middle of the field, different placements are usually not very meaningful.

In the event of a tie after the end of the tournament, the Buchholz rating usually decides which player is better placed in tournaments according to the Swiss system ; Since the Buchholz valuation has the disadvantage that the valuation often depends on chance (players who have received a bye or had to compete against a player who later withdrew from the tournament) or the performance of third parties (it can happen that results from the middle field decide on the order at the top), there are alternative valuation methods. On the one hand, the Elo average of the opponents can simply be calculated, another rating system is “Sum of progress”, with which players should be rewarded who play along from the start.

Modifications of the system in chess

Since the difference in the strength of the opponents is very large in the first rounds, the stronger player almost always wins. Thus the information content of these rounds is low. The idea of ​​the accelerated Swiss system is to give stronger players bonus points before the first round. The stronger players play against each other in the first few rounds. At a later point in time in the tournament, the points will then (gradually) be removed. This results in greater accuracy at the top of the table at the end of the tournament.

The English chess player and mathematician Jonathan Mestel suggested as an alternative to use the eigenvalue of the pairing table to determine the ranking of a tournament. If the main diagonal of the table is filled with a value> 0, such an eigenvalue is secured. The advantage of the system is that a player can no longer be thrown back as far in the ranking as a result of defeats in the last rounds. This applies above all to competitions in which you can achieve a high number of points in one round (team world championship in chess). Likewise, after a weak start, a player can no longer easily get into the front of the field by winning the last round without having played against the leading players. Due to a lack of transparency, however, the system has little chance of success.

Use in pétanque

The Swiss system is used in different variations in the boules sport pétanque . There are tournaments, championships and qualifying competitions in which the Swiss system is played until only one team is without defeat. Other tournaments are played over a predetermined number of rounds.

In the first round there is usually a free drawing. Here, too, in the next rounds either the teams that are one after the other in a ranking updated after each round play against each other, or the groups with the same number of wins are drawn. If a group with the same result has an odd number of teams, a team from the group with the next lowest number of wins is drawn up.

As a result, it can happen that three teams are without defeat in the penultimate round. If the game is played until only one team is without defeat, the tournament is suddenly over if the high-drawn team wins.

There are also tournaments, championships and qualifying competitions in which a few rounds of the Swiss system are played first and then a switch is made to another system. In principle, a certain number of rounds are played in pétanque tournaments according to the Nunkirchen and Maastricht system, after which the tournament is divided into several sub-tournaments. In these sub-tournaments, teams with the same or a similar number of wins play against each other.

The disadvantages of the Buchholz scoring, which are mentioned in the paragraph Application to chess , also apply to pétanque.

The advantage that many pétanque players see in the purely Swiss system is that all teams play until the end of the tournament. Other players see this as a disadvantage, as they have to continue playing even if they no longer have a chance of a good placement. An early exit falsifies the Buchholz rating in particular. This compulsion to continue playing can lead to games being given up.

From 2008, the Fédération Internationale de Pétanque et Jeu Provençal (FIPJP) will hold the preliminary round of the Pétanque World Championship in the Swiss system with Buchholz and Feinbuchholz points (6 rounds).

Web links

Individual evidence

  1. ↑ Swiss championship through the ages Neue Zürcher Zeitung of July 18, 2003, accessed on August 25, 2020.
  2. ^ Editor of the German-language ChessBase chess news
  3. ↑ André Schulz: 125 years of the Swiss system chessbase.com from June 16, 2020.
  4. ^ Daniel Schmand, Marc Schröder, Laura Vargas Koch: A Greedy Algorithm for the Social Golfer and the Oberwolfach Problem . 2020, arxiv : 2007.10704
  5. ^ ESL: Introducing the Swiss format and schedule for the ESL One Cologne offline qualifier. In: ESL One. Retrieved June 10, 2016 .