Rating rules

0. History:   The INGO-Rating is the eldest chess rating system and as I think the best one, too.
              It has been developped by the German Anton H.Ælinger in the fourties and became
              modified for several times in the following years. It was in use by the German
              Chess Federation until 1993. Still today there is a quite similar rating in England:
              the British Grading System.
              To keep the system comprehensible some simplifications have been made for the special
              Xiangqi variant. This Xiangqi version startet in 1990, first tournament to be rated
              was the European Championships in Germany. All following calculations are based on
              this tournament.
              Having his origin in western chess, points are given in "chess" style: win is one point,
              draw half point (in Chinese a win is 2 points, draw is one point).

1. Priciples: a) The "better" player the lower rating. INGO range is from about 10 (world champion)
                 up to 250 (beginner), maximum rating should be 300.
              b) Rating performance has to be calculated strictly in chronological order of the tournaments.
              c) The ratings will be updated after each tournament.
              d) Each INGO rating gets an index that means the number of tournaments that have been
                 calculated for this player.
                 Example: a rating of 120-10 means an INGO of 120, resulting out of 10 rated tournaments.

2. Meanings:  One point difference means one percent more or less of expectancy range.
              Example: If A has a rating of 110 and the average of A’s opponents is also 110, the
              -------- expectancy range is exactly 50%; if the opponents’ average is 100, expectancy
                       range is 10% less than 50%, means 40% (when playing 10 games A should gain 4 points,
                       otherwise his INGO rating has to be changed).

3. Limits:    Due to the linearity of the INGO system, the calculating of expectancy ranges is limited to 50
              points difference. (Of course it is not possible that a player may gain more than one point
              resp. less than 0 points per game..) So we have to cut off in case of opponents’ rating
              differs more than 50 points from yours, when calculating your opponents’ average.
              Example: A’s INGO is 100, his opponents’ 100,170,40, for calculation of average take 100,150,50,
              -------- so the average will be 100 and A should gain 50% that means 1.5 points of the three
                       games (three points in "chinese" counting style).

4. Performance: Row "H" shows the rating performance of a player for the calculated tournament.

5. New INGO:  Abbreviation of INGO is "F" (F-old, F-new). F is normally calculated as follows:
              F-new = (F-old * k + H) / (k + 1), where k means the expeansion coefficience:

6. Coefficience: The lower coefficience, the faster the changes! Normally the expension coefficience is 
                 k = 3; if your index is less than 10, make:
                 k = k - 1; if your index is less than 5, make:
                 k = k - 1; for every game less than 5 in the current tournament, make:
                 k = k + 1; if the tournament’s time schedule is less than 1 hour per player (quickplay),
                 k will be doubled:
                 k = k + k (but herefore see 7.a Restrictions)
                 Example: your rating is 120-4 and you play 3 games in your 5th tournament,
                 -------- your coefficience is:
                          k = 3 (starting value) - 1 (because less than 10 tournaments)
                            - 1 (because less than 5 tournaments)
                            + 2 (2 games less than 5)
                            = 3!
                          If this tournament is a quickplay tournament, k will now be doubled to 6!
                 New rule since 1997: only for overseas competitions of main interest, if time schedule is
                 more than one hour per player and game (Forshang Cup, World Cup): for those tournaments k
                 will be decreased by 1 point, k = k - 1;
                 In any case minimum k has to be 1 - of course!
                 So the fastest rate can be 1:1, the normal one is 3:1.

7. Restrictions: games not to be rated are
                 a) fastplay tournaments (time schedule less than 30 minutes per player and game)
                 b) computer games
                 c) simultaneous games
                 d) forfaith games
                 e) correspondence games and similar competitions, f.e. internet, e-mail, phone, telex ..
                 f) tournaments will only be calculated if they are not elder than one year!

8. Specials:     there are some special rules for calculating of beginners or those players whose
                 strength increases quickly in a short time.

9. Chinese ELO:  I tried to find out the best conversion to the Chinese ELO rating, but as we still do
                 not have more comparative items I propose
                 ELO = 2700 - INGO * 7 resp.
                 INGO = (2700 - ELO) / 7

10. Use of ELO:  the use of existing chinese ELO-ratings is allowed for players without INGO, but only
                 if the normal results seem to become irregular (too many players
                 without INGO rating in the tournament..)

11. Other ELOs:  Other Xiangqi Associations have different ELO rating systems, f.e. Japan, Hongkong and
                 Singapore. The proposed formula as given above can not be used for these national
                 systems, the results can become quite irregular. As far as I know in Taiwan a DAN system  
                 is used. The British Grading system (from western chess, introduced to Xiangqi by
                 Patrick Donovan more than 10 years ago) is nowadays out of use.

Siegfried Huber, German Xiangqi Association
e-mail: Huber.Siegfried@t-online.de