A players grade is the running average of the grade achieved in the last 30 games the player has played in, new players start with a grading of 100.
A players grade for a single game is calculated as follows:
Win -
opponents grade + 50
(capped to players grade + 50)
Loss -
opponents grade - 50
(capped to players grade - 50)
Draw -
opponents grade
(capped to players grade +/- 50)
Players with less than thirty games under their belt are given a provisional grade. The provisional grade is calculated as follows:
Assume player has played 5 games:
grading for five games are:
150, 135, 85, 90, 110
so provisional grade is 150 + 135 + 85 + 90 + 110 + (100 * 25) / 30
This stops a new player jumping up 50 points with a rare, over the odds, win against a far more experienced in their first few games.