From: Albrecht Heeffer <al <at> NETPOINT <dot> BE>
Date: 2 oct 1997
Subject: Re: Round robins

Ross Dickson wrote (October 02, 1997 7:57 AM)

> Is there a simple process for setting up a round robin for an even (say 20)
> number of players so everyone plays everyone else once.

> Obviously it's possible; by trial and error I can set up a matrix for a
> smaller number of players (8) but the trial part seems to grow quite
> rapidly as the number increases.

> I'm hoping there is a "mechanical" way of doing it.

There is an easy "mechanical" way to plan round robin tournaments
which we use for quick play. Let the players sit by side at a long table
with both sides the same number of players and start game 1.
After the game, one player (at a corner) stays seated while all the others
move one chair clockwise. For the next rounds you do the same thing
with the same player that stays seated. After a complete round you
finished a round robin tournament with every one playing every one else.
In chess the player that stays seated has to turn the board after every
game to switch colors. The other boards are not switched.

If you use this as a thought experiment, your matrix will be filled out correctly.

Good luck,

Albrecht Heeffer