EGF Official ratings system

• The event took place not earlier than January 1, 1996.
• The tournament is recognized as EGF classified event.
• Both handicap and even games are accepted.

The rating list includes all "European" players who participated at tournaments that are in the database. An average 1 dan should have Go Rating about 2100 and the difference between grades is set to 100 (6 dan = 2600, 1 kyu = 2000, 20 kyu = 100 etc.). These values are also used to initialize the rating of a new player. The scale of professional grades is set provisionally to 1p = 7d = 2700, 2p = 2730, ... , 9p = 2940. If player's rating drops below -900, it is reset to GoR=-900 which is fixed as the bottom value.

Example 1: The ratings of top European amateur players Guo Juan and Lee Hyuk fall in the region of 3p-4p.

Example 2: The player with GoR = 2050 can be regarded as either a weak 1d or a strong 1k.

Depending on players' tournament results and on the various ranking systems used in different countries, the correspondence between grades and GoR may not work quite well especially for lower kyu grades. However, it gives a relatively good measure of player's strength provided that he/she has participated in at least 3-5 tournaments.

If a player has not participated at any considered tournament for some time (this period is set to 2 years for dan players, 12 months for 1-10 kyu, and 6 months for 11-20 kyu; the actual year/month is not counted), he/she drops out from the current rating list. However, the player's rating is kept in the database of players and it is used once he/she appears again at any tournament in the future.

The rating algorithm was updated starting 2021. The whole database from back in 1996 was recalculated with this algorithm. You can find the old algorithm here.

Ratings are updated by: r' = r + con * (Sa - Se) + bonus
r is the old EGD rating (GoR) of the player
r' is the new EGD rating of the player
Sa is the actual game result (1.0 = win, 0.5 = jigo, 0.0 = loss)
Se is the expected game result as a winning probability (1.0 = 100%, 0.5 = 50%, 0.0 = 0%). See further below for its computation.
con is a factor that determines rating volatility (similar to K in regular Elo rating systems): con = ((3300 - r) / 200)^1.6
bonus (not found in regular Elo rating systems) is a term included to counter rating deflation: bonus = ln(1 + exp((2300 - rating) / 80)) / 5

Se is computed by the Bradley-Terry formula: Se = 1 / (1 + exp(β(r2) - β(r1)))
r1 is the EGD rating of the player
r2 is the EGD rating of the opponent
β is a mapping function for EGD ratings: β = -7 * ln(3300 - r)

The post-tournament ratings are calculated assuming that every player enters the games with all opponents at the same initial (pre-tournament) rating. It means that the ratings are not reevaluated after each game (round) and the "new" ratings are computed from the "old" ones adding all contributions from the games the player completed at a given tournament. In other words, we assume that the ratings of players do not change in the process of one tournament.

If a rank professed by the player had improved significantly (at least by 2 grades for amateur players or by 1 professional grade) with respect to the highest previously professed rank, the rating of the player is reset. This measure helps to deal with fast improving players and with players who participate at included tournaments only occasionally.

The work on the program that calculates the ratings is still in process. In the future, the program should also be used for some statistical purposes and for the maintenance of the database of go players. We welcome any comments and suggestions.

Acknowledgement:

The rating system has been tested, with permission, on the database of professional games provided with the GoGoD Encyclopaedia CD produced by J. Fairbairn and T.M. Hall. We thank R. Kok and Ch. Gerlach for providing us with their databases of tournament results and A. Engels for maintaining a web page which helped us immensely to collect the tournament data. We would also like to thank J.-L.Gailly for advising us on the correct treatment of handicap games. Finally, we acknowledge a help of many people who have contributed with their comments and suggestions, and especially of those who have kept us informed by sending new tournament results.

The results must be submitted through the online parser which is present in the backend section of this website.
In order to be allowed to submit data, you will be requested to register a user account.
If you encounter any problems, report them to egd@europeangodatabase.eu

When the results are sent we need to know:

• the name of the event
• the place (city) where it was hold
• the exact date of the event
• tournament class (or the time limit including byoyomi)
• handicap strategies (if any handicap games occured)

        <opponent's place><symbol>[/<colour>[<h>]] 
where 
        <symbol> is + (a win), - (a loss) or = (jigo)
        <colour> means the colour of stones ('b/w' = black/white)
          <h>    specifies the number of given handicaps
   
Examples: 35=, 23+/w (equivalent to 23+/w0), 11-/b5 

        0+  a free win
        0-  a free round
        0=  a free round (0.5 added to the score and MM)

• goratings.org
• World Go Player Ranking (japanese)
• AGAGD, the AGA Go Database
• French go rating system
• Ratings List | British Go Association
• Brief description of ELO system
• ELO ratings used by FIDE