1. The basic formula when updating the rating values for a person is: d = k * (res - 1/(1+10^((or - tr)/400))) where d is the change (rounded to the nearest integer) k is a koeffisient or is the rating for the opponent tr is the target rating (the rating for the player that is updated) the koeffisient k could be written k(tr) as it is based on the rating to be updatet according to this table: 2240 <= tr 16 1920 <= tr < 2240 20 1560 <= tr < 1920 24 1280 <= tr < 1560 28 1040 <= tr < 1280 32 720 <= tr < 1040 36 tr < 720 40 2. Included into the rating system is also a grade system. Promotions are based on rating and the requirements for promotions and the basic correspondence between grades and rating are summarized in this table: LB MP UB #LB #MP 6 Dan 2440 2540 2640 5 Dan 2240 2340 2440 10 4 Dan 2080 2160 2240 16 8 3 Dan 1920 2000 2080 16 8 2 Dan 1800 1860 1920 14 7 1 Dan 1680 1740 1800 14 7 1 Kyu 1560 1620 1680 14 7 2 Kyu 1460 1510 1560 12 6 3 Kyu 1360 1410 1460 12 6 4 Kyu 1280 1320 1360 12 6 5 Kyu 1200 1240 1280 10 5 6 Kyu 1120 1160 1200 10 5 7 Kyu 1040 1080 1120 10 5 8 Kyu 960 1000 1040 8 4 9 Kyu 880 920 960 8 4 10 Kyu 800 840 880 8 4 11 Kyu 720 760 800 8 4 12 Kyu 640 680 720 6 3 13 Kyu 560 600 640 6 3 14 Kyu 480 520 560 6 3 15 Kyu 400 440 480 6 3 LB means lower bound, MP means midpoint, and UB means upperbound. #LB and #MP are explained in (12). 3. The players are divided into three categories when rating a tournament: - unrated players - players with provisional rating - established players Players whose prior results only include victories or only defeats (including players with no prior results) AND players with less than 9 rated games are considered unrated players. A players who are not an unrated players is a players with provisional rating if the number of rated games are less than 18 otherwise he is an established player. When counting for 9 or 18 games the games in the tournament currently beeing rated are included. 4. Games not played are not rated. So if a player gets a walk-over or a scheduled game is not played for instance because one of the players do not show up, that result has no effect whatsoever when calculating the rating changes. 5. Performance rating of a set of results for a player is the rating a player must have in order to end up with the same rating if you rated the set of results in "the normal way". A single result consists of an outcome (victory, defeat or draw) and the rating of the opponent. Performance rating is not defined if the outcome of all the games is 100% victory or 100% defeat 6. Unrated players get their rating by calculating their performance rating for all prior recorded results and all played games in the current tournament. When recording a result the rating is the post-event rating for the opponent. That is the opponents rating after the current tournament. If the score is 0% the rating is set to 400. If the score is 100% a temporary draw result against the highest rated opponent is inserted. This dummy draw is not recorded afterward, it's just used during the performance rating calculation. 7. A newcomer with a prior grade is rated as an unrated player but starts with a prior result of 2 games consisting of one victory and one defeat against a dummy player with a rating equal to the MP of the players grade (2). This prior grade is assumed to be some kind of offical grade based on actual results achieved. An evaluation performed by a professional or others based on the subjective feel of the quality of some games played does not give a newcomer a prior grade. 8. When rating an established player the formula in (1) is used but the rating of the opponent is the opponts post-event rating. 9. When rating a player with provisional rating the only difference from an established player is that the final rating change is multiplied with 18/n where n is the numer of rated games for the player (including the games in the current tournament). The point is that the rating for provisional players is less founded than established players and should therefore fluxate more. 10. When playing _against_ a player with less than 18 games (including the current tournament), the result is multiplied by (1+(n/18))/2 where n is the opponent number of games. The point is that since the rating of players with less than 18 games are less founded, the rating effect of playing against such players are reduced. 11. To help fast improving players there is a simple bonus system. If a players increases his rating in a tournament by more elo-points than 20+3*n where n is the number of games played, the excess is doubled. However this bonus is not allowed to increase the players rating above his performance rating for the tournament. 12. Promotions. The table from (2) is used An established player has 3 ways of achieving a grade - reach the UB of a grade. - stay above the MP for #MP consecutive games - stay above the LB for #LB consecutive games including 1 game above MP. If a players does not have the required number of games above a limit to get a grade but he is bound to get it if he playes some more games no matter what the outcome is, the grade is awarded now. The calculations are based on the fact that the maximum number of elo-points a player can loose on a single games is the players koeffisient (1). A provisional players can only achieve a grade by reaching the UB of the next grade above. An unrated players can not get a grade, but he keeps any prior grade he has. 5 Dan and 6 Dan is not awarded without the approval of Nihon Shogi Renmei. 13. In the above when the word tournament is used, it would be a little more precise to say table as the basic unit of rating is the table. The players rating are updatet after each table rated. All results in a single table is considered to have happend simultanously. In (12) when counting the number of games with a rating above a limit the total rating change for a tournament is divided equally on all games played. The actual sequence of the games is of no consequence. If at the end of a tournament there is some kind of play-off for instance as a tie breaker for the first place instead of using "quality" points, and the play-off is done at the "same time" as the main tournament then all the results should be entered into the same table. If a play off is set as a seperate event at a later stage it should be in a seperate table. Hovewer the formula in (1) gives meaningless results if the number of games for a single player in the same table is to high. So if the number of games for a single players exceeds 16 the table should be divided into 2 tables. Tournament directors who know that the limit could be reached in their tournament should before the tournament starts decide how the table is to be divided but preferably it should be done by using something equal to a point in time. Rules for rating handicap games are so far not included. Asle Olufsen