Top Chess Engine Championship, formerly known asThoresen Chess Engines Competition (TCEC ornTCEC), is acomputer chess tournament that has been run since 2010. It was organized, directed, and hosted by Martin Thoresen until the end of Season 6; from Season 7 onward it has been organized by Chessdom. It is often regarded as theUnofficial World Computer Chess Championship because of its strong participant line-up and long time-control matches on high-end hardware, giving rise to very high-class chess.[1][2] The tournament has attracted nearly all the top engines compared to theWorld Computer Chess Championship.
After a short break in 2012,[3] TCEC was restarted in early 2013 (asnTCEC)[4] and is currently active (renamed as TCEC in early 2014) with 24/7 live broadcasts of chess matches on its website.
Since season 5, TCEC has been sponsored by Chessdom Arena.[5][6]
The TCEC competition is divided into seasons, where each season happens over a course of a few months, with matches played round-the-clock and broadcast live over the internet. Each season is divided into several tournaments: aLeagues Season, aCup, aSwiss tournament, aFischer Random Chess tournament. Additionally, seasons contain various bonus contests, like the 'Viewer Submitted Opening Bonus'.
Prior to season 21, there was originally one tournament in each season. This tournament consisted of several qualifying stages and one "superfinal", and the winner of the superfinal is called the "TCEC Grand Champion" until the next season. Prior to season 11, the tournament used a cup format, while starting in Season 11, the tournament used a division system. Starting in season 13, there was also a cup tournament consisting of the top 32 engines in the main tournament, resulting in a 5-round single elimination tournament.[7]
Pondering is set to off. All engines run onLinux on the same hardware and use the sameopening book, which is set by the organizers and changed in every stage.Large pages are enabled, and access toendgame tablebases including Syzygy 7-men is permitted.[8] Engines are allowed updates between stages; if there is a critical play-limiting bug, they are also allowed to be updated once during the stage. In previous seasons, if an engine crashes 3 times in one event, it is disqualified to avoid distorting the results for the other engines; however, starting in TCEC Season 20, an engine is allowed to crash any number of times without being disqualified from the current event, although the engine will still be disqualified from future events unless the crash is fixed.[9] TCEC generates anElo rating list from the matches played during the tournament. An initial rating is given to any new participant based on its rating in other chess engine rating lists.
There is no definite criterion for entering into the competition, other than inviting the top participants under active development from various rating lists which can run on their Linux platform. Originally, TCEC used Windows instead of Linux. In addition, eitherXBoard orUCI protocol are required to participate.[10]
Usually chess engines that supportmultiprocessor mode are preferred (8-cores or higher), and engines in active development are given preference. Since TCEC 12, engines like LCZero which use GPUs for neural processing were supported.
Initially, the list of participants was personally chosen by Thoresen before the start of a season. His stated goal was to include "every major engine that is not a direct clone".[11] In TCEC 13, DeusX was banned due to being a clone of Leela, and in TCEC 20, Houdini, Fire, Rybka (engine in Fritz up to TCEC 16), and Critter were banned due to allegations of plagiarism.
The number within the brackets () denote the number of times the engine has won the particular competition.
| Season | Date | TCEC Grand Champion | Elite match/Superfinal score | Runner-Up | ||
|---|---|---|---|---|---|---|
| TCEC Season 1 | Dec 2010 – Feb 2011 | Houdini1.5a (1)[a] | + 12 = 23 - 5 | Rybka4.0 | ||
| TCEC Season 2 | Feb – Apr 2011 | Houdini1.5a (2) | + 9 = 26 - 5 | Rybka4.1 | ||
| TCEC Season 3 | Apr – May 2011 | N/A (season not completed) | ||||
| TCEC Season 4[b] | Jan – May 2013 | Houdini3 (3) | + 6 = 38 - 4 | Stockfish250413 | ||
| TCEC Season 5[c] | Aug – Dec 2013 | Komodo1142 (1) | + 10 = 30 - 8 | Stockfish191113 | ||
| TCEC Season 6 | Feb – May 2014 | Stockfish170514 (1) | + 13 = 45 - 6 | Komodo7x | ||
| TCEC Season 7[d] | Sep – Dec 2014 | Komodo1333 (2) | + 7 = 53 - 4 | Stockfish141214 | ||
| TCEC Season 8 | Aug – Nov 2015 | Komodo9.3x (3) | + 9 = 89 - 2 | Stockfish021115 | ||
| TCEC Season 9 | May – Dec 2016 | Stockfish8 (2) | + 17 = 75 - 8 | |||
| TCEC Season 10 | Oct – Dec 2017 | + 15 = 76 - 9 | Komodo1970.00 | |||
| TCEC Season 11 | Jan – Apr 2018 | Stockfish260318 (3) | + 20 = 78 - 2 | |||
| TCEC Season 12 | Apr – Jul 2018 | Stockfish180614 (4) | + 29 = 62 - 9 | Komodo12.1.1 | ||
| TCEC Season 13 | Aug – Nov 2018 | Stockfish18102108 (5) | + 16 = 78 - 6 | Komodo2155.00 | ||
| TCEC Season 14 | Nov 2018 – Feb 2019 | Stockfish190203 (6) | + 10 = 81 - 9 | LCZerov0.20.2-32930 | ||
| TCEC Season 15 | Mar – May 2019 | LCZerov0.21.1-nT40.T8.610 (1) | + 14 = 79 - 7 | Stockfish19050918 | ||
| TCEC Season 16 | Jul – Oct 2019 | Stockfish19092522 (7) | + 14 = 81 - 5 | AllieSteinv0.5-dev_7b41f8c-n11 | ||
| TCEC Season 17 | Jan – Apr 2020 | LCZerov0.24-sv-t60-3010 (2) | + 17 = 71 - 12 | Stockfish20200407DC | ||
| TCEC Season 18 | May – Jul 2020 | Stockfish202006170741 (8) | + 23 = 61 - 16 | LCZerov0.25.1-svjio-t60-3972-mlh | ||
| TCEC Season 19 | Aug – Oct 2020 | Stockfish202009282242_nn-baeb9ef2d183 (9) | + 18 = 73 - 9 | LCZerov0.26.3-rc1_T60.SV.JH.92-190 | ||
| TCEC Season 20 | Dec 2020 – Feb 2021 | Stockfish20210113 (10) | + 14 = 78 - 8 | LCZero0.27.0d-Tilps-dje-magic_JH.94-100 | ||
| TCEC Leagues Season 21 | May – Aug 2021 | Stockfish14_202107131735 (11) | + 19 = 74 - 7 | LCZero0.28-dev+_69626 | ||
| TCEC Leagues Season 22 | Jan – Apr 2022 | Stockfishdev15_20220401 (12) | + 28 = 63 - 9 | KomodoDragon2894.00 | ||
| TCEC Leagues Season 23 | Aug – Nov 2022 | Stockfishdev16_20221027 (13) | + 27 = 63 - 10 | LCZero0.30-dag-9a9c42d | ||
| TCEC Leagues Season 24 | Feb – Apr 2023 | Stockfishdev-20230409 (14) | + 20 = 64 - 16 | LCZero0.30-dag-a9b25c2b | ||
| TCEC Leagues Season 25 | Aug – Oct 2023 | Stockfishdev-20231010 (15) | + 27 = 50 - 23 | LCZero0.31-dag-e429eeb-BT3 | ||
| TCEC Leagues Season 26 | May – Jun 2024 | Stockfishdev-20240513 (16) | + 31 = 52 - 17 | LCZero0.31-dag-5350a2e-BT4 | ||
| TCEC Leagues Season 27 | Oct 2024 – Jan 2025 | Stockfishdev-20241208 (17) | + 35 = 47 - 18 | LCZero0.31-dag-f7fb268-BT4 | ||
| TCEC Leagues Season 28 | Jun – Sep 2025 | Stockfishdev-20250824 (18) | + 36 = 43 - 21 | LCZero0.33-dev-b4e98c1-BT4 | ||
| Tournament | Date | Winner | Finals score | Runner-up |
|---|---|---|---|---|
| TCEC Cup 1 | Oct 2018 | Stockfish270918 (1) | + 1 = 7 - 0 | |
| TCEC Cup 2 | Jan 2019 | LCZerov0.20.1-32742 (1) | + 1 = 7 - 0 | |
| TCEC Cup 3 | May 2019 | LCZerov0.21.1-nT40.T6.532 (2) | + 2 = 7 - 1 | Stockfish19042711 |
| TCEC Cup 4 | Oct 2019 | Stockfish19100908 (2) | + 1 = 7 - 0 | LCZerov0.22.0-nT2 |
| TCEC Cup 5 | Apr 2020 | Stockfish202004181536 (3) | + 1 = 3 - 0 | LCZerov0.24-sv-t60-3010 |
| TCEC Cup 6 | Jul 2020 | AllieSteinv0.7_dev2-net_15.0 (1) | + 1 = 3 - 0 | LCZerov0.26.0_sv-t60-4229-mlh_opt2 |
| TCEC Cup 7 | Nov 2020 | Stockfish2020102823_nn-2eb2e0707c2b (4) | + 1 = 3 - 0 | LCZerov0.26.3_T60.SV.JH.92-270 |
| TCEC Cup 8 | Feb 2021 | Stockfish202102202249 (5) | + 1 = 7 - 0 | LCZero0.27.0-pr1509_JH.94-100 |
| TCEC Cup 9 | Oct 2021 | Stockfishdev15_20211015 (6) | + 1 = 3 - 0 | LCZero0.28-dev+_609958 |
| TCEC Cup 10 | May 2022 | Stockfishdev16_2022051413 (7) | + 2 = 9 - 1 | KomodoDragon3 |
| TCEC Cup 11 | Jan 2023 | LCZero0.30-dag-dcb4ece9-BT2-3250000 (3) | + 2 = 13 - 1 | Stockfishdev16_202301021914 |
| TCEC Cup 12 | Jul 2023 | Stockfishdev-20230713 (8) | + 10 = 9 - 9 | LCZero0.31-dag-dd64c7e-T1 |
| TCEC Cup 13 | Mar 2024 | Stockfishdev-20240217 (9) | + 4 = 17 - 1 | LCZero0.31-dag-5c1051f-BT4 |
| TCEC Cup 14 | Oct 2024 | Stockfishdev-20240928 (10) | + 12 = 13 - 11 | LCZero0.31-dag-4167c1e-BT4 |
| TCEC Cup 15 | Jun 2025 | Stockfishdev-20250602 (11) | + 6 = 13 - 3 | LCZero0.31-dag-c5f4683-BT4 |
| Tournament | Date | Winner | Runner-up |
|---|---|---|---|
| TCEC Swiss 1 | Apr 2021 | KomodoDragon2679.08 (1) | Stockfish20210310 |
| TCEC Swiss 2 | Nov – Dec 2021 | KomodoDragon2.5.1 (2) | Stockfish14.1_20211101 |
| TCEC Swiss 3 | May – Jul 2022 | Stockfishdev16_20220521 (1) | LCZero0.30-dev+_783363 |
| TCEC Swiss 4 | Jan – Feb 2023 | Stockfishdev-20230114 (2) | LCZero0.30-dag-6b5f9451, KomodoDragon3.2 |
| TCEC Swiss 5 | Jun - Jul 2023 | Stockfishdev-20230614 (3) | LCZero0.31-dag-dd64c7e-T1 |
| TCEC Swiss 6 | Jan – Feb 2024 | LCZero0.31-dag-a487796-BT3 (1) | Stockfishdev-20240114 |
| TCEC Swiss 7 | Sep 2024 | LCZero0.31-dag-321205e-BT4 (2) | Stockfish17 |
| TCEC Swiss 8 | Apr - Jun 2025 | Stockfishdev-20250513 (4) | LCZero0.31-dag-c5f4683-BT4 |
Replaced by TCEC FRD.
| Tournament | Date | Winner | Final/Superfinal score | Runner-up |
|---|---|---|---|---|
| TCEC FRC 1 | Oct – Nov 2019 | Stockfish191107 (1) | + 10 = 10 - 0 | AllieSteinv0.5_c328142-n11.1 |
| TCEC FRC 2 | Nov 2020 | Stockfish202011101829_nn-c3ca321c51c9 (2) | + 8 = 42 - 0 | LCZerov0.26.3_T60.SV.JH.92-330 |
| TCEC FRC 3 | Mar 2021 | KomodoDragon2671.00 (1) | + 2 = 47 - 1 | Stockfish20210226 |
| TCEC FRC 4 | Dec 2021 – Jan 2022 | Stockfishdev15_2021121915 (3) | + 13 = 28 - 9 | LCZero0.29-dev+_610826 |
| TCEC FRC 5 | Jul 2022 | Stockfishdev16_20220705 (4) | + 17 = 20 - 13 | LCZero0.30-dag-bord_784038 |
| TCEC FRC 6 | May 2023 | Stockfishdev-20230507 (5) | + 15 = 23 - 12 | LCZero0.31-dag-1f90473-T1 |
Replaced by TCEC FRD. In DFRC, the start positions of the pieces are randomized independently for both players.
| Tournament | Date | Winner | Final score | Runner-up |
|---|---|---|---|---|
| TCEC DFRC 1 | Jul – Aug 2022 | Stockfishdev16_202207131801 (1) | + 18 = 23 - 9 | LCZero0.30-dag-bord-dfrc_784038 |
| TCEC DFRC 2 | May - Jun 2023 | Stockfishdev-20230528 (2) | + 10 = 33 - 7 | LCZero0.31-dag-590cd9ba-T1 |
In FRD, which has superseded both FRC and DFRC, the qualifying rounds are played in the Fischer Random System and the finals in the double Fischer Random System.
| Tournament | Date | Winner | Final score | Runner-up |
|---|---|---|---|---|
| TCEC FRD 1 | Nov - Dec 2023 | Stockfishdev-20231116 (1) | + 11 = 29 - 10 | LCZero0.31-dag-a487796-BT3 |
| TCEC FRD 2 | Jun - Jul 2024 | Stockfishdev-20240612 (2) | + 20 = 16 - 14 | LCZero0.31-dag-5350a2e-BT4 |
| TCEC FRD 3 | Feb 2025 | Stockfishdev-20250126 (3) | + 13 = 25 - 12 | LCZero0.31-dag-c93c6a8-BT4 |
| TCEC FRD 4 | Sep - Oct 2025 | Stockfishdev-20250913 (4) | + 18 = 18 - 14 | LCZero0.33-dev-f20db7e-BT4 |
Engines are limited to4 KiB (4,096 bytes) in program size.
| Tournament | Date | Winner | Final score | Runner-up |
|---|---|---|---|---|
| TCEC 4kI | Dec 2022 | ice49e94b82 | 45.5/48 (RR) | 4ku1.0 |
| TCEC 4kII | May 2023 | ice4v3 | + 5 = 15 - 4 | 4ku3.0 |
| TCEC 4kIII | Dec 2023 – Jan 2024 | 4ku4.0 | + 13 = 30 - 7 | ice44 |
| TCEC 4kIV | Aug 2024 | ice45 | + 29 = 20 - 1 | 4ku5.0 |
| TCEC 4kV | Apr 2025 | ice46 | + 29 = 20 - 1 | 4ku5.1 |
| Tournament | Date | Winner | Runner-up |
|---|---|---|---|
| TCEC Season 6FRC | Jun – Jul 2014 | Stockfish260614 | Houdini4 |
| TCEC Season 9Rapid[a] | Sep 2016 | Komodo1692.19 | |
| TCEC Season 10 Rapid | Dec 2017 | Stockfish051117 | |
| TCEC Season 10 Blitz | Dec 2017 | Komodo1959.00 | Stockfish051117 |
| TCEC Season 23 Chess Bonus | Aug 2022 | Stockfishdev16_202208061357 | KomodoDragon3.1 |
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