Help notes: Rtg - Rating of a player.
Rc - Average rating of rated opponents.
Rc note: A difference in rating of more than 350 points will be
counted for rating purposes as though it were a difference of 350
points.
W - Total score against rated opponents.
N - Number of games against rated opponents.
K val - K is the development coefficient.
K = 25 for a player new to the rating list until he has completed events with a total of at least 30 games.
K = 15 as long as a player`s rating remains under 2400.
K = 10 once a player`s published rating has reached 2400, and he has also completed events with a total of at least 30 games. Thereafter it remains permanently at 10. More info
Chess Ratings