Round Robin Pairings

Porter By board number. Normal Colors Rewrite screen
Crenshaw Sequential Players. Reversed Colors New screen Crenshaw & Sequential are USCF defaults.
Min. Moves 2nd half of Round Robin or splice in late players
Court Balanced
Enter number of players (do last): Check for double round robin
(Internal) Board Number Players are initially seated in every other chair and rotate by at most one position.

Sequential players As above except except only odd boards are displayed from left to right starting from the "ghost" board, then even boards from right to left. Because sequential players were seated in every other chair, they will appear to be seated next to the next sequential higher or lower pairing numbered players. This is how the tables appear in Official Rules (US. Chess Federation).

Min. Moves Same as sequential except that alternate rounds are displayed in reverse order and only half the players move each round.

Example for 12 players in board order in Rd. 1:
 1:    1-12   7-6   11-2   8-5   10-3   9-4

12 players on Sequential Players in Rd. 1 (Same for Min. Moves, but reverses on even numbered rounds):
1:     1-12 11-2   10-3   9-4    8-5    7-6

Porter is a simple modification to the original Berger tables which started with Player 1 starting with two whites while another player started with two blacks.  E.g., with 12 players, 1-6 had white against 12-7 respectively and 7 starts with two blacks.  The modification is 1 has white against 12, but 2-6 have black against 11-7. Click here for an example. Crenshaw corrected the same problem, but opponents are in descending order.

In chess, the first opponent has White. For other games or sports this may also indicate color or home/away status, who calls a coin toss, the winner of the coin toss, or ignored.  Court Balanced isn't applicable to chess but may be helpful when assigning tennis courts or time slots randomly which may or may not be balanced.   It randomly assigns games to columns, but a better resource is here.

To generate random pairing numbers, click here. To display each player's schedule in Porter order, click here;  players can create their own schedules here.  

© 2013 by Warren Porter

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