Achess rating systemis a system used inchessto estimate the strength of a player, based on their performance versus other players. They are used by organizations such asFIDE,theUS Chess Federation(USCF or US Chess),International Correspondence Chess Federation,and theEnglish Chess Federation.Most of the systems are used to recalculate ratings after a tournament or match but some are used to recalculate ratings after individual games. Popularonline chesssites such asChess.com,Lichess,andInternet Chess Clubalso implement rating systems. In almost all systems, a higher number indicates a stronger player. In general, players' ratings go up if they perform better than expected and down if they perform worse than expected. The magnitude of the change depends on the rating of their opponents. TheElo rating systemis currently the most widely used (though it has many variations and improvements). The Elo-like ratings systems have been adopted in many other contexts, such asother games like Go,inonline competitive gaming,and indating apps.[1]
The first modern rating system was used by theCorrespondence Chess League of Americain 1939. Soviet player Andrey Khachaturov proposed a similar system in 1946.[2]The first one that made an impact on international chess was the Ingo system in 1948. The USCF adopted the Harkness system in 1950. Shortly after, theBritish Chess Federationstarted using a system devised byRichard W. B. Clarke.The USCF switched to theElo rating systemin 1960, which was adopted byFIDEin 1970.[3]
Ingo system
editThis was the system of the West German Chess Federation from 1948 until 1992, designed by Anton Hoesslinger and published in 1948. It was replaced by an Elo system,Deutsche Wertungszahl.It influenced some other rating systems.
New players receive a high, fixed starting score. Players' new ratings centre on the average rating of entrants to their competition: then if having achieved better than a net draw set of result,minusthe number of percentage points it is over 50% (e.g. a 12–4 or 24–8 wins-to-losses result is, as ever, noted as a 75% tournament outcome) – if having achieved worse than this then the number, again in percent, isaddedto the average of the tournament entrants' scores; thus in all cases recalibrating all players after each tournament completely. A consequence is at most 50 points gained or shed per tournament (namely by a totally winning or totally losing participant) away from thetournament average.Unlike other modern, nationally used chess systems, lower numbers indicate better performance.[4]
Harkness system
editThis system was noted inChess Reviewby tournament organizerKenneth Harkness,who expounded his invention of it in articles of 1956, 14 years later. It was used by the USCF from 1950 to 1960 and other leagues.
When players compete in a tournament, the average rating of their competition is calculated. If a player scores 50%, they receive the average competition rating as their performance rating. If they score more than 50%, their new rating is the competition average plus 10 points per percentage point exceeding 50. If they score less, their new rating is the competition average minus 10 points per percentage point shy of 50.[5]
Example
editA player with a rating of 1600 plays in an eleven-round tournament and scores 2½–8½ (22.7%) against competition with an average rating of 1850. This is 27.3% below 50% (50–22.7%), so their new rating is 1850 − (10 × 27.3) = 1577.[6]
English Chess Federation system
editTheECF grading systemwas used by theEnglish Chess Federationuntil 2020. It was published in 1958 byRichard W. B. Clarke.Each game has a large potential effect. Points (grades) are never immediately effective for every game won, lost or drawn, in a registered competition (including English congresses, local and county leagues, and registered, approved team events) but are averaged into personal grade (ECF Grade) over a cycle of at least 30 games.
A player's contributing score for such averaging is taken to be their opponent's grade (but the gap is deemed to be 40 points, if greater than such a grade gap). However this is adjusted by adding 50 points for a win, subtracting 50 points for a loss, and making no adjustment for a draw. Negative grades are deemed to be nil, so a personal score of 50 arose quickly in the lower leagues and experienced novices aspire to a 100 grading. The cyclical averaging and cycle-persistent Grades are its hallmarks. The maximum gain in a single cycle is 90 points, which would entail beating much higher-rated opponents at every match. The opposite applies to losses.
To convert between ECF and Elo grades, the formula ELO = (ECF * 7.50) + 700 was sometimes used.[7]
Elo rating system
editThe Elo system was invented byArpad Eloand is the most common rating system. It is used byFIDE,other organizations and some Chess websites such asInternet Chess Clubandchess24.com.Elo once stated that the process of rating players was in any case rather approximate; he compared it to "the measurement of the position of a cork bobbing up and down on the surface of agitated water with a yard stick tied to a rope and which is swaying in the wind".[8]Any attempt to consolidate all aspects of a player's strength into a single number inevitably misses some of the picture.
FIDE divides all its normal tournaments into categories by a narrower average rating of the players. Each category is 25 rating points wide. Category 1 is for an average rating of 2251 to 2275, category 2 is 2276 to 2300, etc. Women's tournaments currently commence 200 points lower, including its Category 1.[9]
| Rating range | Category |
|---|---|
| 2700+ | No formal title, but sometimes informally called "super grandmasters"[11] |
| 2700–2500 | Grandmasters (GM) |
| 2499–2400 | International Masters (IM) |
| 2399–2300 | FIDE Masters (FM) |
| 2299–2200 | Candidate Masters (CM) |
| 2199–2000 | Experts |
| 1999–1800 | Class A, category 1 |
| 1799–1600 | Class B, category 2 |
| 1599–1400 | Class C, category 3 |
| 1399–1200 | Class D, category 4 |
| 1199–1000 | Class E, category 5 |
| Below 1000 | Novices |
The USCF uses the USCF system, a modification of the Elo system, in which the K factor varies and it gives bonus points for superior performance in a tournament.[12]USCF ratings are generally 50 to 100 points higher than the FIDE equivalents.[13]
| Category | Rating range |
|---|---|
| Senior master | 2400 and up |
| National master | 2200–2399 |
| Expert | 2000–2199 |
| Class A | 1800–1999 |
| Class B | 1600–1799 |
| Class C | 1400–1599 |
| Class D | 1200–1399 |
| Class E | 1000–1199 |
| Class F | 800–999 |
| Class G | 600–799 |
| Class H | 400–599 |
| Class I | 200–399 |
| Class J | 100–199 |
Example
editElo gives an example of amending the rating ofLajos Portisch,a 2635-rated player before his tournament, who scores 10½ points of a possible 16 winning points (as this is against 16 players). First, the difference in rating is recorded for each other player he faced. Then the expected score, against each, is determined from a table, which publishes this for every band of rating difference. For instance, one opponent wasVlastimil Hort,who was rated at 2600. The rating difference of 35 gave Portisch an expected score of "0.55". This is an impossible score as not 0,1⁄2or 1 but as this is higher than 0.5 even a draw will very slightly damage Portisch's rating; conversely a draw will very slightly improve Hort's rating.
Portisch's expected score is summed for each of his matches, which gave a total expected score of 9.66. Then the formula is:
- new rating = old rating + (K × (W−We))
K is 10; W is the actual match/tournament score; Weis the expected score.
Portisch's new rating[14]is 2635 + 10×(10.5−9.66) = 2643.4.
Linear approximation
editElo devised a linear approximation to his full system, negating the need for look-up tables of expected score. With that method, a player's new rating is
whereRnewandRoldare the player's new and old ratings respectively,Diis the opponent's rating minus the player's rating,Wis the number of wins,Lis the number of losses,C= 200 andK= 32. The term(W-L) / 2is the score above or below 0.ΣD / 4Cis the expected score according to: 4C rating points equals 100%.[15]
The USCF used a modification of this system to calculate ratings after individual games ofcorrespondence chess,with aK= 32 andC= 200.[16]
Glicko rating system
editThe Glicko system is a more modern approach, which was invented by Mark Glickman as an improvement of the Elo system. It is used byChess.com,Free Internet Chess Serverand other online chess servers. The Glicko-2 system is a refinement of the original Glicko system and is used byLichess,Australian Chess Federationand other online websites.
Turkey UKD system
editTSF (Turkey Chess Federation) uses a combination of ELO and UKD system.[17]
USA ICCF system
editTheICCF U.S.A.used its own system in the 1970s. It now uses the Elo system.
Deutsche Wertungszahl
editThe Deutsche Wertungszahl system replaced the Ingo system in Germany.
Chessmetrics
editThe Chessmetrics system was invented byJeff Sonas.It is based on computer analysis of a large database of games and is intended to be more accurate than the Elo system.
Universal Rating System
editThe Universal Rating System was developed byMark Glickman,Jeff Sonas,J. Isaac Miller and Maxime Rischard, with the support of theGrand Chess Tour,theKasparov Chess Foundation,and theChess Club and Scholastic Center of Saint Louis.[18]
Rating systems using computers as a reference
editMany rating systems give a rating to players at a given time, but cannot compare players from different eras. In 2006, Matej Guid andIvan Bratkopioneered a new way of rating players, by comparing their moves against the recommended moves of achess engine.The authors used the programCraftyand argued that even a lower-ranked program (Elo around 2700) could identify good players.[19]In their follow-up study, they usedRybka 3to estimate chess player ratings.[20]
In 2017, Jean-Marc Alliot compared players usingStockfish 6with an ELO rating around 3300, well above top human players.[21]
Chronology
edit- 1933 – The Correspondence Chess League of America (nowICCF U.S.A.) is the first national organization to use a numerical rating system. It chooses the Short system which clubs on the west coast of the US had used. In 1934 the CCLA switched to the Walt James Percentage System but in 1940 returned to a point system designed by Kenneth Williams.
- 1942 –Chess Reviewuses the Harkness system, an improvement of the Williams system.
- 1944 – The CCLA changes to an improved version of the Williams system devised by William Wilcock. A slight change to the system was made in 1949.
- 1946 – TheUSSR Chess Federationuses a non-numerical system to classify players.
- 1948 – The Ingo system is published and used by the West German Chess Federation.
- 1949 – The Harkness system is submitted to the USCF. The British Chess Federation adopts it later and uses it at least as late as 1967.[22]
- 1950 – The USCF starts using the Harkness system and publishes its first rating list in the November issue ofChess Life.Reuben Fineis first with a rating of 2817 andSammy Reshevskyis second with 2770.[23]
- 1959 – The USCF names Arpad Elo the head of a committee to examine all rating systems and make recommendations.
- 1961 – Elo develops his system and it is used by the USCF.[24]It is published in the June 1961 issue ofChess Life.[25]
- 1970 –FIDEstarts using the Elo system.Bobby Fischeris at the top of the list.[26]
- 1978 – Elo's book (The Rating of Chessplayers, Past and Present) on his rating system is published.
- 1993 –Deutsche Wertungszahlreplaces the Ingo system in Germany.
- 2001 – theGlicko systemby Glickman is published.[27]
- 2005 – Chessmetrics is published by Jeff Sonas.[28]
- 2006 – Matej Guid and Ivan Bratko publish the research paper "Computer Analysis of World Chess Champions", which rates champions by comparing their moves to the moves chosen by the computer programCrafty.[29]
- 2017 – Jean-Marc Alliot publishes the research paper "Who is the Master?", which rates champions by comparing their moves toStockfish 6.[21]
See also
editNotes
edit- ^"Tinder matchmaking is more like Warcraft than you might think - Kill Screen".2017-08-19. Archived fromthe originalon 2017-08-19.Retrieved2024-02-04.
According to Tinder CEO Jonathan Badeen, Tinder uses a variation of ELO scoring to determine how you rank among the site's userbase, and therefore, which profiles to suggest to you and whose queues your profile shows up in.
- ^(Hooper & Whyld 1992:332)
- ^(Hooper & Whyld 1992:332)
- ^(Harkness 1967:205–6).
- ^(Harkness 1967:185–88)
- ^(Harkness 1967:187)
- ^"The calculation of ECF Grades on a monthly basis".English Chess Federation.Retrieved2022-07-08.
- ^Chess Life,1962.
- ^FIDE Handbook, Section B.0.0,FIDEweb site
- ^Elo, 1978, p. 18
- ^"How to face a Super Grandmaster?".Saint Louis Chess Club.January 25, 2019.
- ^(Just & Burg 2003:259–73)
- ^(Just & Burg 2003:112)
- ^(Elo 1978:37)
- ^(Elo 1978:28–29)
- ^"The United States Chess Federation - CC Ratings Explanation".www.uschess.org.
- ^"TSF UKD Bilgi Sistemi".ukd.tsf.org.tr.
- ^"Universal Rating System".2017-01-03.
- ^Riis, Søren (2 November 2006)."Review of" Computer Analysis of World Chess Champions "".Chessbase.
- ^Riis, Søren (11 November 2011)."Review of" Using Chess Engines to Estimate Human Skill "".Chessbase.
- ^abAlliot, Jean-Marc (2017)."Who is the Master?".ICGA Journal.39:3–43.doi:10.3233/ICG-160012.
- ^(Harkness 1967:184)
- ^(Lawrence 2009)
- ^(Harkness 1967:184)
- ^(Elo 1978:197)
- ^(Elo 1978:68, 89)
- ^"Glickman website".Archived fromthe originalon June 11, 2010.
- ^"Welcome to the Chessmetrics site".chessmetrics.com.Archived fromthe originalon November 15, 2011.
- ^Guid, Matej; Bratko, Ivan. "Computer analysis of world chess champions".International Computer Games Association Journal.29(2): 3–14.
References
edit- Elo, Arpad(1978),The Rating of Chess Players, Past and Present,Arco,ISBN978-0-668-04721-0
- Harkness, Kenneth(1967),The Official Chess Handbook,McKay
- Hooper, David;Whyld, Kenneth(1992),The Oxford Companion to Chess(2nd ed.), Oxford University Press,ISBN978-0-19-280049-7
- Just, Tim; Burg, Daniel B. (2003),U.S. Chess Federation's Official Rules of Chess(5th ed.), McKay,ISBN978-0-8129-3559-2
- Lawrence, Al(February 2009), "Ratings, Rules, and Rockets: USCF's 2nd decade: 1949–1958",Chess Life,2009(2): 9