7. Grading7. Grading Jon Diamond Mon, 22/02/2010 - 15:03
Last updated Sep 2018 by Pat Ridley
For more information about the Rating System we operate see the Rating System FAQ, which uses the European Go Federation (EGF) rating system.
Many British tournaments are run on the McMahon system, which tries to pair players of equal strength. This relies on players entering the tournament at a realistic grade so that fair games between players can be achieved. Many European tournaments are also run on the McMahon system, so again we would like to ensure that our players perform satisfactorily in European events. Consequently the aim of our ratings policy is:
- keep British grades reasonably close to the European average
- help players get a fair draw at British McMahon events and
- help players perform on equal terms in European tournaments.
7.1 Rated Games
It is recognised that not all players are able to play in every tournament and some players' published ratings may lag excessively behind their actual playing strength. To address this issue, our policy regarding which games count towards rating points is as follows:
- All Association approved events which have time limits at or better than the EGF class C limits are submitted for ratings. The main exclusions are Pairgo, and Team events.
- Where isolated players cannot get to tournaments frequently enough, they can arrange 'rating games' of tournament standard against other Association rated players to be played outside Association events.
- Affiliated clubs may also arrange 'club ladder events', which can be submitted for ratings.
- We encourage travel to ensure that these 'extra games' do not lead to frequent pairings within isolated groups.
- The rules governing rated games played outside Association tournaments are found in Rated Games.
7.2 Tournament Entry Grade and Rating Resets
The policy is:
- If you play in a reasonable number of tournaments and are making average progress enter them at a grade equal to the strength listed on the current version of our ratings page, rounded to the nearest whole number. This includes cases where the player's rounded strength is higher than his official grade.
- If you are 3 kyu or below and play in many tournaments, and are making very rapid progress consider promoting 1 stone more than you would normally to get at least a 2 stone rating reset.
- If you can only get to tournaments infrequently and cannot arrange suitable rating games then contact your club secretary or our ratings officer to discuss an appropriate tournament entry grade when you do next attend.
- Strong kyu players can gain a rating reset to 1 dan or a 2 dan in extreme circumstance if this is agreed in advance with us.
- A dan player must agree any rating reset in advance with us.
7.3 Players with On-line Grades only
We encourage on-line players to enter over-the-board tournaments. In order to establish a relation between on-line server grades and our strengths we will be setting up a system to collect information from players who play in tournaments as well as on-line. Until a meaningful correlation between server and our grades is established, the following guide will apply for an on-line player entering one of our tournaments for the very first time or after a long absence:
- For kyu players the grade = server grade - 2
- For dan players the grade is also = server grade - 2, but the highest entry grade is 2 dan unless agreed ahead of time by us.
7.4 Dan Certificates and Grades
Since November 2003, British Go Association dan certificates have been awarded based on our ratings, which in turn are based on the European rating system. You will be awarded a dan certificate under the following conditions.
- You must have played 10 or more rated games in a sequence of tournaments.
- Your strength at the end of the last tournament in the sequence must be at least as high as your starting strength in the first tournament of the sequence. You can find your strength in the BGA ratings page.
- If your strength reaches X.0 dan at the end of the last tournament in the sequence, you are awarded an X dan certificate.
- You must be a member of the British Go Association during the entire qualifying tournament sequence.
The first time you play in a rated tournament, your strength is initialised to your tournament entry grade - which may not be very accurate. Only after you have played in several tournaments does it settle down to a reasonable measure of your playing ability. The conditions above ensure that certificates are not awarded during this initial settling down period.
An instability can also occur after a rating reset, when you already have a rating, but enter at a grade two stones higher than your previous highest grade. In this case your rating may drop below the reset value, but as long as it eventually rises again to reach the next dan level threshold, you gain a certificate when all the above conditions are met.
In the first instance tournament directors are encouraged to be proactive in ensuring that their players are entering at realistic grades. The results of all our tournament are scrutinised and submitted to the EGF by our ratings official. If anomalous entry grades are present in the results, submission of games to the EGF rating system may be delayed and the following procedure adopted:
- The issue is first discussed with the tournament director, and if this does not resolve the problem, then:
- The anomaly is discussed in Council.
- Any decision taken by Council and the tournament director (TD) is communicated to both TD and player.
- In most cases the results published on the web will remain unaffected.
7.6 Complaints Procedure
It is very much hoped that players' entry grades are essentially self managed, and much information is provided to help players determine their entry grades. However, if any player wishes to complain about the published rating of either themselves or another player on our rating list then the following procedure must be adopted:
- The player makes the complaint in writing to the ratings officer.
- The complaint is discussed in Council.
- The Council decision is communicated to the player(s) involved as appropriate.
7.7 Calculation of Strength
Strengths are calculated from ratings in the European Go Database:
strength = (rating - 2100)/100 (rounded to one decimal place)
Until early 2017 we used a linear regression of player's grades vs rating to calculate the player strength as presented in our rating page. Although this process gave plausible results in the early years of the rating system, the method was degraded by the drop in the average rating of all European players. By early 2017, a nominal shodan (rating 2100) had a strength of 1.7d rather than 1.0d. The procedure was abandoned early in 2017.