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The Chess Variant Pages



Game Courier Ratings for %

This file reads data on finished games and calculates Game Courier Ratings (GCR's) for each player. These will be most meaningful for single Chess variants, though they may be calculated across variants. This page is presently in development, and the method used is experimental. I may change the method in due time. How the method works is described below.

There may be a delay while it reads the database and calculates results.

Game Filter: Log Filter: Group Filter:
Tournament Filter: Age Filter: Status Filter:
SELECT * FROM FinishedGames WHERE Rated='on'

You are viewing ratings based on a wildcard that includes all Chess variants played on Game Courier. This is not as meaningful as ratings based on a single variant, which you may find in the Related menu for each preset.

Game Courier Ratings for %
Accuracy:69.21%68.84%68.65%
NameUseridGCRPercent wonGCR1GCR2
Hexa Sakkbosa601852136.5/151 = 90.40%18271877
Play Testerplaytester1847153.5/179 = 85.75%18051889
Francis Fahystamandua1837247.0/298 = 82.89%18261847
dax00dax001827161.0/167 = 96.41%18121842
Kevin Paceypanther1775548.0/771 = 71.08%17681782
Homo Simiaalienum174946.0/60 = 76.67%17371762
Carlos Cetinasissa1746712.5/1079 = 66.03%17141777
Cameron Milesshatteredglass171115.0/17 = 88.24%17081713
Jochen Muellerleopold_stotch169555.0/92 = 59.78%16841706
H Spetyura169013.0/13 = 100.00%16711709
Gary Giffordpenswift168260.5/85 = 71.18%15871777
Fergus Dunihofergus167063.5/101 = 62.87%16631677
Jose Carrilloj_carrillo_vii166488.5/156 = 56.73%16641665
Vitya Makovmakov3331647418.0/871 = 47.99%16101684
Tim O'Lenatim_olena163617.5/27 = 64.81%16401632
CSS Dixielandcssdixieland163018.0/25 = 72.00%16141646
David Paulowichdavid_64162611.0/13 = 84.62%16301622
Stephen Williamsneph161911.0/12 = 91.67%15741663
shift2shiftshift2shift161511.0/19 = 57.89%16071624
Vitya Makovmakov16127.5/8 = 93.75%16101614
Charles Danielfrozen_methane161135.0/64 = 54.69%15711650
Andreas Kaufmannandreas16077.0/7 = 100.00%16091605
Daniel Zachariasarx1604171.0/302 = 56.62%16301578
Erik Lerougeerik1594141.5/262 = 54.01%16671520
Pericles Tesone de Souzaperitezz15888.0/8 = 100.00%15881588
Jeremy Thompsonjezzat15818.0/15 = 53.33%16011562
ctzctz157912.0/17 = 70.59%15531604
kokoszkokosz15777.0/8 = 87.50%15591595
attack hippoattackhippo15765.5/7 = 78.57%15711582
Abdul-Rahman Sibahisibahi157516.0/23 = 69.57%15651585
TH6notath615737.0/12 = 58.33%15701576
Plamen Draganovdraganov15724.0/4 = 100.00%15711573
Alexander Trotterqilin15714.0/4 = 100.00%15711571
Stephen Stockmanstevestockman156810.0/16 = 62.50%15731564
Jenard Cabilaomgawalangmagawa156811.0/23 = 47.83%15841551
Christine Bagley-Joneszcherryz15673.5/5 = 70.00%15651569
je jujejujeju156336.5/61 = 59.84%15551570
John Gallantbigjohn156116.0/28 = 57.14%15451577
Raymond Dlewel156013.0/22 = 59.09%15781543
Isaac Felpsattacker14415585.0/6 = 83.33%15591557
Thor Slavenskyslavensky15555.0/7 = 71.43%15351575
Nicholas Wolffnwolff15549.0/15 = 60.00%15741534
Nicola Caridiniccar15543.0/3 = 100.00%15571550
Roberto Lavierirlavieri200315503.0/3 = 100.00%15451555
S Ssim15436.0/9 = 66.67%15311554
carlos carloscarlos154216.0/27 = 59.26%15211564
michirmichir15422.0/2 = 100.00%15411543
pallab basupallab153831.0/60 = 51.67%15281548
Sandra#Paul BRANDLYARDsandravers13067515383.0/4 = 75.00%15361539
Neil Spargospargo15373.0/4 = 75.00%15291544
Tom e4ktome4k15362.0/2 = 100.00%15351536
Greg Strongmageofmaple1535106.0/219 = 48.40%15901480
Todd Witterstoddw15342.0/2 = 100.00%15331535
Eric Greenwoodcavalier15344.0/6 = 66.67%15441524
Nicholas Wolffmaeko153365.5/142 = 46.13%15521515
Julien Coll Moratfacteurix15332.0/3 = 66.67%15301535
Jake Palladinocerebralassassin15312.0/2 = 100.00%15271535
Matthew Montchalinmatthew_montchal15313.0/4 = 75.00%15291533
Fred Koktangram15282.0/3 = 66.67%15291527
joe rosenbloombootzilla15282.0/3 = 66.67%15271529
Uwe Kreuzercaissus15272.0/2 = 100.00%15241530
Chuck Leegyw6t152617.5/39 = 44.87%15161536
Máté Csarmaszcsarmi15267.0/16 = 43.75%15371515
Joseph DiMurotrojh15261.0/1 = 100.00%15341519
Yeinzon Rodríguez Garcíayeinzon15241.0/1 = 100.00%15271520
Adrian Alvarez de la Campaadrian15243.5/6 = 58.33%15231524
Tom Westtwrecks15211.0/1 = 100.00%15241519
dicepawndicepawn15201.0/1 = 100.00%15231518
von raidervonraider15201.0/1 = 100.00%15191520
Larry Wheelerbrainburner15191.0/1 = 100.00%15211518
Dougbughouse15191.0/1 = 100.00%15201518
Richard Titlertitle15181.0/1 = 100.00%15191518
strings 808017424strings80801742415181.0/1 = 100.00%15181518
Trevor Savagesavage15181.0/1 = 100.00%15181518
yas kumkumagai15181.0/1 = 100.00%15181518
David Levinsmidrael15181.0/1 = 100.00%15181518
whitenerdy53whitenerdy5315181.0/1 = 100.00%15181518
jj15181.0/1 = 100.00%15181518
Antonio Bruzzitotonno_janggi15181.0/1 = 100.00%15181518
eunchong leeeunchong15181.0/1 = 100.00%15181518
Angel47 Usmanangel4715181.0/1 = 100.00%15181518
calebblazecalebblaze15181.0/1 = 100.00%15181518
Jan Żmudajanzmuda15171.0/1 = 100.00%15181517
Garrett Smithgmsmith15171.0/2 = 50.00%15241511
Titus Ledbettertbl215171.0/1 = 100.00%15181517
M Wintherkalroten15171.0/1 = 100.00%15181516
Hesham Husseinegy_sniper15171.0/1 = 100.00%15171517
bosa6bosa615171.0/1 = 100.00%15151519
Aaron Smithzirtoc15162.5/5 = 50.00%15121520
Samuel Hoskinscouriergame15161.0/2 = 50.00%15271505
Georges-Clounet Jesuispartoutgeorgesclounet15161.0/1 = 100.00%15131519
Antonio Barratotonno15161.0/1 = 100.00%15141518
pink sockpickett_aaron15152.0/3 = 66.67%15151515
Simon Langley-Evansslangers15151.5/2 = 75.00%15131516
Georg Spengleravunjahei15139.0/28 = 32.14%15041522
spiptorben15131.0/2 = 50.00%15111515
xxmanxxman15131.0/2 = 50.00%15181508
Max Kovalmaxkoval15131.0/1 = 100.00%15071519
Leon Careyleoncarey15121.0/1 = 100.00%15071518
Nathanlokor15111.0/2 = 50.00%15111512
pheko Motaungcouriermabovini151135.5/70 = 50.71%15631458
Antoine Fourrièreantoinefourriere15091.5/2 = 75.00%15081511
mystery playercentipede15092.0/5 = 40.00%15121505
Anthony Viensstarkiller15082.0/4 = 50.00%15001517
As Bardhiasbardhi15081.0/2 = 50.00%15131502
xeongreyxeongrey15078.0/17 = 47.06%15131501
Zachary Wadeazost1215073.0/5 = 60.00%15011513
Natalia Dolindowhitetiger15051.0/2 = 50.00%15061504
Graeme Neathamgrayhawke15041.0/2 = 50.00%15011507
Albert Vámosiblackrider_4815031.0/4 = 25.00%15161490
Joe Joycejoejoyce150321.5/64 = 33.59%14741531
Colin Adamslionhawk15021.0/2 = 50.00%15051500
Gee Beegdimension15021.0/2 = 50.00%15021502
Hans Henrikssonhasurami15022.0/4 = 50.00%14921512
Tom Trenchtomdench9515020.5/1 = 50.00%15001503
Kent Weschlerperplexedibex15001.0/3 = 33.33%15011500
noy noynoy14993.0/7 = 42.86%14821516
Colin Weaveruselessgit14991.0/4 = 25.00%14971500
Thom Dimentunwiseowl14982.0/5 = 40.00%15001497
Eni Lienili149811.5/46 = 25.00%15181479
Juan Pablo Schweitzer Kirsingerdefender14971.0/2 = 50.00%14951499
Max Fengwowimbob111214941.0/3 = 33.33%14971492
John Smithultimatecoolster14943.0/9 = 33.33%14931496
Armin Liebhartlunaris149324.0/55 = 43.64%14641522
DFA Productions70nyd014920.0/1 = 0.00%14961489
don anezdonanez14920.0/1 = 0.00%14961488
Michael Christensenjustsojazz14920.0/1 = 0.00%14961487
hubergerdhubergerd14920.0/1 = 0.00%14961487
vikvik14910.0/1 = 0.00%14961486
kunkunkunkun14910.0/1 = 0.00%14971486
Hugo Mendes-Nuneshugo199514910.0/1 = 0.00%14971485
Fabner Cruz Gracilianofabner14910.0/1 = 0.00%14971484
Bob Brownbobhihih14900.0/1 = 0.00%14971484
wyatt wyattquimssarcasm14900.0/1 = 0.00%14971483
jesus babyboypokechamp14900.0/1 = 0.00%14971482
ugo judeugojude14900.0/1 = 0.00%14951484
Ricardo Florentinoricmf14900.0/1 = 0.00%14921487
potato imaginatorpotato14890.0/1 = 0.00%14921486
John Badgerjbadger14890.0/1 = 0.00%14951484
Hsa Saidh14890.0/1 = 0.00%14971481
Urvish Desaiurvishdesai14890.0/1 = 0.00%14921486
makomako14890.0/1 = 0.00%14961482
Milton Haddockmiltonhaddock14890.0/1 = 0.00%14951483
xerisianxxerisianx14890.0/1 = 0.00%14931485
Hafsteinn Kjartanssonhnr0114890.0/1 = 0.00%14961481
Anders Gustafsonancog14890.0/1 = 0.00%14961481
Esperllynmogik14890.0/1 = 0.00%14951482
loveokenloveoken14890.0/1 = 0.00%14931484
Matias I.tsatziq14880.0/1 = 0.00%14951481
Steve Polleychessfan5914880.0/1 = 0.00%14931484
Erlang Shenerlangshen14880.0/1 = 0.00%14951481
Jason Stehlyjasonstehly14880.0/1 = 0.00%14931483
Éric Manálangedubble1914880.0/1 = 0.00%14931482
Ben Reinigerbenr14870.0/1 = 0.00%14931481
Ivan Velascoswordandsilver14870.0/1 = 0.00%14911483
Four PlayerChessfourplayerchess14870.0/1 = 0.00%14911482
Rob Brownsteelhead14870.0/1 = 0.00%14911483
Lamai grouplamai14870.0/1 = 0.00%14921481
DJ Linickdjlinick14860.0/1 = 0.00%14911482
Dead Accountqqzlbpdilchr14860.0/1 = 0.00%14911481
Bradlee Kingstonbrad1914860.0/1 = 0.00%14891482
Mike Smolowitzmjs170114850.0/1 = 0.00%14891481
Joseph Yoderjjosseepphh14850.0/1 = 0.00%14841486
Brock Sampsonthe_iron_kenyan14850.0/1 = 0.00%14871483
William Crewscrewsdude14850.0/1 = 0.00%14881482
Andy Thomasandy_thomas14850.0/1 = 0.00%14871483
Ronald Brierleybenwb14850.0/1 = 0.00%14841486
Luis Menendezpleyades2114850.0/1 = 0.00%14881482
Nasmichael Farrismichaeljay14850.0/1 = 0.00%14881482
Alexandr Kremenakremen14850.0/1 = 0.00%14891481
dghanddghand14850.0/1 = 0.00%14851485
Travis Comptonironlance14850.0/1 = 0.00%14881481
Gus Dunihoduniho14850.0/1 = 0.00%14881481
Lwebato14850.0/1 = 0.00%14851484
Siwakorn Songragskyhistory14850.0/1 = 0.00%14861483
anon anonchessvar114850.0/1 = 0.00%14851484
Jacob Eugenioe45w14840.0/1 = 0.00%14871482
john applejohnnyappleseed714840.0/1 = 0.00%14861483
Julianredpanda148417.0/35 = 48.57%14641504
László Gadosdani198314841.0/4 = 25.00%14801489
Doge Masterdogemaster14840.0/1 = 0.00%14871481
Boyko Ahtarovzdra4148410.0/23 = 43.48%14851483
Derek Mooseelevatorfarter14841.0/3 = 33.33%14841484
maolan leonardruby14840.0/1 = 0.00%14861482
higuyzzz91028 Charles Kimdallastexas14840.0/1 = 0.00%14871481
James Sprattwhittlin14840.0/1 = 0.00%14871481
Paolo Porsiapillau14840.0/1 = 0.00%14861481
sixtysixty14840.0/3 = 0.00%14871480
Jeremy Goodyamorezu14840.0/1 = 0.00%14851482
Kyle Hagemanfoofoo9914840.0/1 = 0.00%14871480
andy lewickiherlocksholmes14840.0/1 = 0.00%14861481
yi fang liuliuyifang14830.0/1 = 0.00%14861481
Solomon Salamasol71014830.0/1 = 0.00%14821484
Antony Vailevichjabberw0cky114830.0/1 = 0.00%14831484
Turk Osterburgtalen3141593141514830.0/1 = 0.00%14851481
manolo manolomanolo14830.0/1 = 0.00%14831483
Paul2memorysorowthorn14830.0/1 = 0.00%14831482
Dan Kellydankelly14830.0/1 = 0.00%14841481
wabbawabba14830.0/1 = 0.00%14841481
MichaÅ‚ Jarskihookz14830.0/1 = 0.00%14821483
Giuseppe Acciarocoopwie14832.0/5 = 40.00%14771488
Andreas Bunkahlebunkahle14820.0/1 = 0.00%14831482
Jose Canceljoche14820.0/1 = 0.00%14831482
Tony Quintanillatony_quintanilla14820.0/1 = 0.00%14821483
Roberto Cassanotamerlano14820.0/1 = 0.00%14841481
btstwbtstw14820.0/1 = 0.00%14841481
Uri Bruckbruck14820.0/2 = 0.00%14921473
Hung Daobyteboy14820.0/1 = 0.00%14831481
cdpowercdpower14820.0/1 = 0.00%14841480
scythian blunderq1234514820.0/2 = 0.00%14851479
Nicholas Archerchess_hunter14820.0/2 = 0.00%14871477
Minh Dangminhdang14820.0/1 = 0.00%14811482
anna colladoapatura_iris14820.0/1 = 0.00%14811482
Joseph Grangercdafan14820.0/1 = 0.00%14811482
luigi mattagigino4214820.0/1 = 0.00%14801483
Thomas Meehanorangeaurochs14820.0/1 = 0.00%14821481
legendlegend14820.0/2 = 0.00%14901473
Robin Sneijderrobinwooter214820.0/1 = 0.00%14811482
Виктор Байгужаковbajvik14820.0/1 = 0.00%14821481
Jun Ocampojunpogi14810.0/2 = 0.00%14851478
Wottonwotton14810.0/1 = 0.00%14811481
Harry Gaoharrygao14810.0/1 = 0.00%14811481
y kumyasuhiro14810.0/1 = 0.00%14811481
Ryan Schwartzshunoshi14810.0/1 = 0.00%14811481
ben chewben558214810.0/1 = 0.00%14811481
14810.0/1 = 0.00%14811481
Babo Jeffbabojeff14810.0/1 = 0.00%14811481
wonsang leewonsang14810.0/1 = 0.00%14811481
Vitali Maslanskivitali_1014810.0/1 = 0.00%14811481
paulblazepaulblaze14810.0/1 = 0.00%14811481
blundermanblunderman14810.0/1 = 0.00%14811481
Abe Anonapostateabe14810.0/1 = 0.00%14801482
Mark Thompsonmarkthompson14810.0/2 = 0.00%14921469
arcasorarcasor14800.0/1 = 0.00%14791481
Aurelian Floreacatugo1480252.5/730 = 34.59%15641396
rederikrederik14800.0/1 = 0.00%14781481
Diego M.diego14790.0/3 = 0.00%14831475
championchampion14790.0/2 = 0.00%14841475
N Wolffpoint01iv14791.0/3 = 33.33%14731485
andres fuentesxabyer14790.0/2 = 0.00%14801477
voicantvoicant14790.0/1 = 0.00%14761481
Bn Emnelk11414790.0/2 = 0.00%14831474
trtztrtz gfghtrtztrtz14780.0/2 = 0.00%14831474
ologyology14780.0/1 = 0.00%14751481
Ivan Kosintsevbombino14780.0/1 = 0.00%14741481
Francesco Casalinofrancesco14780.0/2 = 0.00%14831472
qidb602qidb60214770.0/2 = 0.00%14831470
Rechefiltr is Firecryinto14760.0/1 = 0.00%14711481
Frank Istvánistvan6014760.0/2 = 0.00%14851467
Francisco Magalhãeslowcarbknight14760.0/1 = 0.00%14701481
Ivan Ivankillbill22514760.0/1 = 0.00%14701481
Alexander Krutikovlonewolf14761.0/4 = 25.00%14721479
tedy efwttei27fmrw7de14750.0/1 = 0.00%14691481
John Twycrossjt14750.0/2 = 0.00%14741476
Nathan Holdenlinsolv14750.0/1 = 0.00%14681482
wdtrwdtr14750.0/3 = 0.00%14791471
Todor Tchervenkovtchervenkov14741.0/4 = 25.00%14741474
Steve Hsteve_201014740.0/2 = 0.00%14691479
Charles Gilmancharles_gilman14740.0/2 = 0.00%14731474
Szling Ozecszling_ozec14730.0/3 = 0.00%14761471
Lennon Figueiredogiwseppe14731.0/4 = 25.00%14711476
Pablo Denegrideep_thinker14730.0/2 = 0.00%14761471
Travis Comptonblackrood14720.0/2 = 0.00%14711474
cherokee malansailorhertzog14710.0/2 = 0.00%14781464
danielmacduffdanielmacduff14710.0/3 = 0.00%14681474
Kacper Rutkowskikacperrutkowski14700.0/2 = 0.00%14731467
dfe6631dfe663114700.0/2 = 0.00%14651474
Zoli M Zoltánbaltazarprof14700.0/5 = 0.00%14821457
andrewthepawnandrewthepawn14690.0/2 = 0.00%14671472
iuchi45iuchi4514690.0/2 = 0.00%14691470
jeremy diniericharles_bukowski14690.0/2 = 0.00%14671471
Pat Quexionezsuperpatzermaste14680.0/4 = 0.00%14681469
Adam DeWittchessshogi14680.0/3 = 0.00%14741462
Sergey Biryukovsbiryukov14680.0/4 = 0.00%14681468
A tomiatomi14684.5/16 = 28.12%14601476
Memedes Lulagiwseppe314670.0/2 = 0.00%14691466
Zac Sparxkrinid14660.0/2 = 0.00%14671465
Donut Donutdonutdonut14650.0/2 = 0.00%14651465
Scott Crawfordmathemagician14650.0/7 = 0.00%14741455
playshogiplayshogi14640.0/2 = 0.00%14661463
Michael Nelsonmikenels14640.0/2 = 0.00%14611466
Namik Zadenamik14630.0/2 = 0.00%14611465
andy lewickietaoni14630.0/2 = 0.00%14611464
michael collinsverderben14631.0/5 = 20.00%14681458
Michael Huntkronsteen3314580.0/3 = 0.00%14491468
Andy Lewickiondraszek14570.0/3 = 0.00%14491464
Graemegraemecn14560.0/3 = 0.00%14541459
louisvlouisv14550.0/3 = 0.00%14581453
Николай Сокольскийalexich14550.0/4 = 0.00%14611449
Nick Wolffwolff145526.0/72 = 36.11%14261484
John Langleyjonners14520.5/4 = 12.50%14521451
Dayrom Gilallahukbar14510.0/3 = 0.00%14511452
Michael Schmahlmschmahl14505.0/15 = 33.33%14591441
Linn Russellfreakat14490.0/3 = 0.00%14491449
Aaron Maynardvopi14491.0/6 = 16.67%14431454
Scott McGrealagentofchaos14497.0/19 = 36.84%14531444
Joshua Tsamraku14485.0/12 = 41.67%14241473
Adalbertus Kchewoj14481.0/5 = 20.00%14411454
heche60heche6014432.0/12 = 16.67%14441442
vitaliy ravitztalsterch14422.0/15 = 13.33%14291456
dmitarzvonimirdmitarzvonimir14420.0/5 = 0.00%14391446
Jeremy Goodjudgmentality144243.5/127 = 34.25%14351449
Jean-Louis Cazauxtimurthelenk14412.0/10 = 20.00%14361445
Sagi Gabaysagig7214360.5/16 = 3.12%14241449
Evan Jorgensonsabataegalo14360.0/7 = 0.00%14241448
Dmitry Strelyabba8314350.0/6 = 0.00%14481421
Evert Jan Karmanevertvb14352.5/11 = 22.73%14181451
Phoenix TKartkr10101014332.0/9 = 22.22%14381428
Matthew La Valleesherman10114316.0/23 = 26.09%14101452
Jon Dannjon_dann14300.0/4 = 0.00%14261433
juan rodriguezrodriguez142711.5/38 = 30.26%14421411
Вадря Покштяpokshtya14225.0/19 = 26.32%14051439
Paul Rapoportnumerist14220.0/6 = 0.00%14271416
Jack Zavierubersketch14200.0/6 = 0.00%14151426
Alan Galetornadic14203.0/20 = 15.00%14211419
boukineboukine14204.0/13 = 30.77%13861453
Daniil Frolovflowermann14203.0/16 = 18.75%14071433
Arthur Yvrardtorendil14160.0/7 = 0.00%14111421
Jeremy Hook10011014142.0/30 = 6.67%14121416
Samuel de Souzasamsou14110.0/8 = 0.00%14111411
John Davischappy14103.0/17 = 17.65%14011419
yellowturtleyellowturtle14100.0/10 = 0.00%14111408
Evan Jorgensonejorgens14090.0/7 = 0.00%13981420
George Dukegwduke140842.5/117 = 36.32%13521464
Митя Стрелецкийsocrat8314020.0/10 = 0.00%13881416
darren paullramalam139813.5/100 = 13.50%13721423
mrxx2016mrxx201613930.0/12 = 0.00%14031384
Bogot Bogotolbog138612.0/44 = 27.27%13701402
Jarid Carlsonsacredchao137013.0/68 = 19.12%13391401
Nakanaka13580.0/11 = 0.00%13281387
Сергей Маэстроfantomas13511.0/31 = 3.23%13501351
Diogen Abramelindanko13310.0/35 = 0.00%13161345
Oisín D.sxg130942.0/197 = 21.32%12921326
wdtr2wdtr2129721.5/155 = 13.87%12821312
Сергей Бугаевскийbugaevsky12953.0/56 = 5.36%12851304
Alisher Bolsaniraja8512760.0/46 = 0.00%12521300
Richard milnersesquipedalian12709.0/167 = 5.39%13061235
per hommerbergper3112672.0/61 = 3.28%12451288

Meaning

The ratings are estimates of relative playing strength. Given the ratings of two players, the difference between their ratings is used to estimate the percentage of games each may win against the other. A difference of zero estimates that each player should win half the games. A difference of 400 or more estimates that the higher rated player should win every game. Between these, the higher rated player is expected to win a percentage of games calculated by the formula (difference/8)+50. A rating means nothing on its own. It is meaningful only in comparison to another player whose rating is derived from the same set of data through the same set of calculations. So your rating here cannot be compared to someone's Elo rating.

Accuracy

Ratings are calculated through a self-correcting trial-and-error process that compares actual outcomes with expected outcomes, gradually changing the ratings to better reflect actual outcomes. With enough data, this process can approach accuracy to a high degree, but error remains an essential element of any trial-and-error process, and without enough data, its results will remain error-ridden. Unfortunately, Chess variants are not played enough to give it a large data set to work with. The data sets here are usually small, and that means the ratings will not be fully accurate.

One measure taken to eke out the most data from the small data sets that are available is to calculate ratings in a holistic manner that incorporates all results into the evaluation of each result. The first step of this is to go through pairs of players in a manner that doesn't concentrate all the games of one player in one stage of the process. This involves ordering the players in a zig-zagging manner that evenly distributes each player throughout the process of evaluating ratings. The second step is to reverse the order that pairs of players are evaluated in, recalculate all the ratings, and average the two sets of ratings. This allows the outcome of every game to affect the rating calculations for every pair of players. One consequence of this is that your rating is not a static figure. Games played by other people may influence your rating even if you have stopped playing. The upside to this is that ratings of inactive players should get more accurate as more games are played by other people.

Fairness

High ratings have to be earned by playing many games. They are not available through shortcuts. In a previous version of the rating system, I focused on accuracy more than fairness, which resulted in some players getting high ratings after playing only a few games. This new rating system curbs rating growth more, so that you have to win many games to get a high rating. One way it curbs rating growth is to base the amount it changes a rating on the number of games played between two players. The more games they play together, the more it approaches the maximum amount a rating may be changed after comparing two players. This maximum amount is equal to the percentage of difference between expectations and actual results times 400. So the amount ratings may change in one go is limited to a range of 0 to 400. The amount of change is further limited by the number of games each player has already played. The more past games a player has played, the more his rating is considered stable, making it less subject to change.

Algorithm

  1. Each finished public game matching the wildcard or list of games is read, with wins and draws being recorded into a table of pairwise wins. A win counts as 1 for the winner, and a draw counts as .5 for each player.
  2. All players get an initial rating of 1500.
  3. All players are sorted in order of decreasing number of games. Ties are broken first by number of games won, then by number of opponents. This determines the order in which pairs of players will have their ratings recalculated.
  4. Initialize the count of all player's past games to zero.
  5. Based on the ordering of players, go through all pairs of players in a zig-zagging order that spreads out the pairing of each player with each of his opponents. For each pair that have played games together, recalculate their ratings as described below:
    1. Add up the number of games played. If none, skip to the next pair of players.
    2. Identify the players as p1 and p2, and subtract p2's rating from p1's.
    3. Based on this score, calculate the percent of games p1 is expected to win.
    4. Subtract this percentage from the percentage of games p1 actually won. // This is the difference between actual outcome and predicted outcome. It may range from -100 to +100.
    5. Multiply this difference by 400 to get the maximum amount of change allowed.
    6. Where n is the number of games played together, multiply the maximum amount of change by (n)/(n+10).
    7. For each player, where p is the number of his past games, multiply this product by (1-(p/(p+800))).
    8. Add this amount to the rating for p1, and subtract it from the rating for p2. // If it is negative, p1 will lose points, and p2 will gain points.
    9. Update the count of each player's past games by adding the games they played together.
  6. Reinitialize all player's past games to zero.
  7. Repeat the same procedure in the reverse zig-zagging order, creating a new set of ratings.
  8. Average both sets of ratings into one set.


Written by Fergus Duniho
WWW Page Created: 6 January 2006