Swiss Chess Tournaments

The term “Swiss chess tournament” does not always refer to a tournament in Switzerland, although it’s a country where chess is quite popular. The Swiss style of tournament pairings is a method whereby the top half of the rankings play against the bottom half of the rankings. Such a tournament is commonly called just “a Swiss” or “a 7-round Swiss” or similar.

The Basic Algorithm

The basic idea is that every set of players in every round is split in half, with the top half playing the bottom half. For example, if there are 10 players in ranking order, then the games are:

  • 1st vs 6th
  • 2nd vs 7th
  • 3rd vs 8th
  • 4th vs 9th
  • 5th vs 10th

Actually the colors alternative, so it would actually be 7th (Black) vs 2nd (White), but we’ll ignore colors for now. So in the very first round, it’s easy to know who you’re playing. And if you’re Players 1 through 5, you got an easier lower-rated opponent, but players 6 through 10 got a difficult higher-rated opponent.

At the next round, the same idea applies, but to multiple subsets. All of the people on the same number of points are split in half, with the top half of that group playing the bottom half of that group. So after the first round, there are 3 groups: players on 1 point, half a point, or zero points. Each of those 3 groups are then split in half and paired.

Things get more tricky eventually. If there’s an odd number of players in any group, the Swiss system has to “borrow” a player from the group below it. And there are some other complexities that arise such as byes, withdrawals, penalties, new arrivals, and so on.

Details of Swiss Pairing System

The basic conceptual features of the Swiss play system include:

  • If you win, you tend to get a harder game.
  • If you lose, you tend to get an easier opponent (easier than your last opponent; not necessarily rated lower than you!).
  • If you draw, you tend to get an easier opponent, but not as easy as if you had lost.
  • You tend to play a person who has the same number of points as you in the tournament.
  • The early rounds of a tournament tend to be easy for the top players and difficult for the weaker players! But there are often “upsets” and “draws” in the games too.
  • The top seeds tend not to be playing each other until nearer to the end of the tournament.
  • You cannot play the same person twice.
  • Colors generally alternate, although sometimes you get the same color two games in a row.

The Swiss system is the most common pairing method used in official tournaments. It is quite often used in “weekenders” where there are 5, 6, or 7 rounds.

Other Types of Pairings

Some of the alternative methods of tournament pairings are:

  • Accelerated Swiss
  • Round Robin
  • Double Round Robin
  • Knockout Tournaments
  • World Championships