*Originally posted by Svin1*

**Anybody who plays someone rated 700 points lower than himself takes the same risk--it's not just Ironman. I think it's fair because it discourages people from gathering easy points against much weaker players.**

this is not quite true .... ironman has a different rating rule from the rest of us .... 2100+ players also have a different rule.

http://www.redhotpawn.com/help/index.php?help=faq

"

How is my rating calculated?

When you join, you are given a rating of 1200.

If you enter into a rated game, your rating will be recalculated on its completion so long as at least two moves have been made by each player.

Note: Until you have completed 20 games your rating may go down even when you win a game!

Until you complete 20 games, you will have a provisional rating. This rating is calculated as the average of all the games you have played. Each game is scored as being your opponent's rating (for a draw), your opponent's rating plus 400 (for a win), or your opponent's rating minus 400 (for a loss). If your opponent is also on a provisional rating, then the 400s above become 200s. If your opponent has played fewer than five games then their rating is treated as 1200 when calculating your rating.

Players are rated using the following formula:

New Rating = Old Rating + K * (Score - Win Expectancy)

**K is a constant (32 for 0-2099, 24 for 2100-2399, 16 for 2400 and above)**
Score is 1 for a win, 0.5 for a draw and 0 for a loss.

The Win Expectancy is calculated using the following formula :

Win Expectancy = 1 / (10^((OpponentRating-YourRating)/400)+1)

The Win Expectancy is used in the rating calculation but is interesting on its own. For example, the calculation below is for a rating difference of 200. This shows that if you have a rating 200 points higher than another player, you can expect to beat them, on average, three times for each four games played.

Win Expectancy = 1 / (10^(-200/400)+1) = 0.76

Note: ^ = "to the power of", e.g. 2^3=8.

If you have a non-provisional rating and you play a provisional-rated player, then you receive (or lose) only half the number of rating points you would normally. If the provisionally-rated player has played fewer than five games, then their rating is treated as 1200 when calculating your rating.

"

i do not understand the need for this "k", it seems unnecessary.

i suspect it is only here to stop players like ironman embarassingly getting a rating higher than kasparov.

**rhp ratings lose legitimacy when players have a rating higher than kasparov.**
but here we are a correpondence site and so the ratings gap must be greater than o.t.b.

here we go from casual unskilled players moving very fast ... up to skilled players googling opening books and regularly taking many days to calculate important moves.

i say get rid of the double standards ... make k=32 for everyone.