How does rating system work?

I would like to know how the rating system works on this site. There are 2 ratings (a number and kyu/dan), there is also an number behind +/- I would like to understand how this system works. I cannot find the explanation on this site

This thread should help: OGS rating


There’s also this very basic explanation in our documentation :|-Creating-and-Adjusting-Your-Account#your-rating

It looks like it could do with a little expansion about uncertainly and the table of ranks. If someone is keen, it’s wiki :slight_smile:


Sorry for answering with links, but to me it feels like I answered the basic questions hundreds of times (I cannot find my older/longer posts myself).

Of you have further questions, feel free to ask.


@flovo I have some questions about the Glicko2 point table we have in our profile. I tried to find some explanation on the forum but it seems my searching skills dropped with covid confinement.

Looking at this table I have a lot of questions:

  1. Looking to a column, the last one for example, how can be possible to have a general correspondence rating higher than the 19x19 correspondence rating if there is no other game in smaller go board played? How can the general value increase?
  2. The combination never played (like for example live game in 9x9 in the example above) that are shown dimmed with a default value of 1150 +/- 350 do contribute to the general rating of the column?
  3. If the answer at point 2) is yes, Does it make sense to play some game in such combination with the objective to raise a so low value affecting the general value of the column?
  4. if the answer at point 2) is no, Does it make sense to avoid such a combination if you don’t like at all - for example - playing at 9x9? Otherwise, a single bad performance can affect forever your general value of the column.
  5. Is it relevant the number of games played in each combination for the corresponding general value? Or it affects only the error bar?
  6. Why the estimated ranking in terms of kyu/dan is reported only in the general upper left corner plot and not in any other combination? Does make sense to have different kyu/dan levels in different conditions/sizes?
  7. why there is a mismatch between general rating in decimal kyu/dan values calculated in the plot and the number reported above your avatar? Do these numbers come from the same algorithm?

I don’t want to chase you if you already answered to these questions. Even a well-pointed link is enough for my curiosity. Thank you in advance.


General is not an average of the other values, each number is calculated completely independently from the others.

No, since they’re calculated independently, games you have not played are not analysed. Each number is calculated by comparing a subset of your games with a subset of your opponents games, at no point are your own ratings compared with any of your other ratings.

  1. No

Also no, the effect of any one game is going to have very little effect on your overall rank.

  1. Still no.

The kyu/dan ranks were manually mapped to overall rating points by anoek based on known “anchor points” (basically, players with a very reliable and consistent rank). Since this was specifically mapped to the overall rating, and the other ratings are only loosely connected to it at best, using the rank conversion formula on these cosmetic ratings could be seen as disingenuous.

Generally, there should not be a mismatch, but sometimes there are some server delays or cookie errors that temporarily result in them being out of sync, usually, this can be resolved by finishing another ranked game.