From: Pieter Stouten CARBON DMPC COM> Date: 2 oct 1997 Subject: FWD: Re: Round robins The enclosed message is forwarded on behalf of Marc Theeuwen. ---------------------------------------------------------------------------- | From: Marc_Theeuwen mail amsinc com | Date: Thu, 02 Oct 97 03:27:00 EST | To: The Shogi Discussion List techunix technion ac il> | Subject: Re: Round robins There is an easy solution for round robins pairings: 1) Number all players sequentially and give "Mr Bye" a number as well in case of an odd number from 1 to 2n. 2) Pairings for the first round are 1 vs 2n, 2 vs 2n-1, 3 vs 2n-2, ..., n vs n+1 3) Second and later rounds: let player 1 stay seated at the same table and rotate all other cyclically, i.e. player 2 moves to the table where player 3 was sitting the round before, 3 moves to the former table of number 4, ...., and player 2n moves to the former table of player 2. Illustration for 6 players: Round 1: 1 2 3 vs 6 5 4 Round 2: 1 6 2 vs 5 4 3 Round 3: 1 5 6 vs 4 3 2 Round 4: 1 4 5 vs 3 2 6 Round 5: 1 3 4 vs 2 6 5 For this simple example, you can easily verify that everybody has played everybody else once and once only. Mathematically, it can easily be proved to work for any number of players, so have fun with your tournament. The tournament for doubles teams is not clear to me from the description. Could you give an example for a small number of participants.