Mittens (chess)

Mittens was released on January 1, 2023, as part of a New Year event on Chess.com. It was one of five engines released, all with names related to cats.{{Cite web |last=Zulkiflee |first=Sarah |date=January 7, 2023 |title=What is Mittens? A chess nightmare behind an innocent kitty bot |url=https://esports.gg/news/gaming/what-is-mittens-chess-cat-bot/ |access-date=January 9, 2023 |website=Esports.gg |language=en |archive-date=January 9, 2023 |archive-url=https://web.archive.org/web/20230109203553/https://esports.gg/news/gaming/what-is-mittens-chess-cat-bot/ |url-status=live }}{{Cite web |date=January 23, 2023 |title=Il gattino contro cui tutti vogliono giocare a scacchi |url=https://www.ilpost.it/2023/01/23/mittens-chess-com-gattino-scacchi/ |access-date=January 24, 2023 |website=Il Post |language=it-IT |archive-date=January 23, 2023 |archive-url=https://web.archive.org/web/20230123175514/https://www.ilpost.it/2023/01/23/mittens-chess-com-gattino-scacchi/ |url-status=live }}{{Cite web |last=Cuthbertson |first=Anthony |date=January 24, 2023 |title='Psycho' AI bot crashes Chess.com and drives record users to chess site |url=https://www.independent.co.uk/tech/chess-bot-ai-mittens-site-down-b2267987.html |access-date=January 24, 2023 |website=The Independent |language=en |archive-date=January 24, 2023 |archive-url=https://web.archive.org/web/20230124132241/https://www.independent.co.uk/tech/chess-bot-ai-mittens-site-down-b2267987.html |url-status=live }} The other engines released were named Scaredy Cat, rated 800; Angry Cat, rated 1000; Mr. Grumpers, rated 1200 and Catspurrov (a pun on Garry Kasparov),{{Cite web |last=Pahwa |first=Nitish |date=January 24, 2023 |title=How Chess.com Built Mittens, the Evil Cat Bot Destroying Players' Souls |url=https://slate.com/technology/2023/01/chess-dot-com-mittens-bot.html |access-date=January 24, 2023 |website=Slate |language=en |archive-date=January 24, 2023 |archive-url=https://web.archive.org/web/20230124201912/https://slate.com/technology/2023/01/chess-dot-com-mittens-bot.html |url-status=live }} rated 1400.{{Cite web |last=Raymond |first=Art |date=January 19, 2023 |title=Mittens the chess-playing cat bot proving hard to tame |url=https://www.deseret.com/2023/1/19/23562766/chess-playing-bot-mittens-the-cat-has-snark-and-game-leave-you-in-shreds |access-date=January 20, 2023 |website=Deseret News |language=en |archive-date=January 20, 2023 |archive-url=https://web.archive.org/web/20230120011435/https://www.deseret.com/2023/1/19/23562766/chess-playing-bot-mittens-the-cat-has-snark-and-game-leave-you-in-shreds |url-status=live }} As part of the announcement, a picture of each engine was accompanied by a short description of its character. The description given for Mittens suggested that the engine was hiding something, reading:{{Cite web |date=January 1, 2023 |title=Cat Bots: The Purrfect Way To Start The Year |url=https://www.chess.com/news/view/chesscom-announces-cat-bots |website=Chess.com}}

{{Block quote|text=Mittens likes chess… But how good is she?}}

Of the five engines released, Mittens was by far the most popular. In December 2023, Chess.com re-released Mittens as part of a "best of 2023" group of chess bots made to showcase their most popular bots of the year.{{Cite web |date=December 1, 2023 |title=Mittens Is Back! Celebrate The Holiday Season By Playing Chess Against Fan-Favorite Bots |url=https://www.chess.com/news/view/announcing-fan-favorite-bots |website=Chess.com}}

File:Anatoly Karpov 2017 april (cropped).jpg|left]]

Mittens was conceptualized by Chess.com employee Will Whalen.{{cite web |date=February 7, 2023 |title=Meet the innocent looking cat that upended the chess world |url=https://www.cnn.com/videos/business/2023/02/07/cat-chess-bot-mittens-contd-orig-fj.cnn-business |access-date=February 8, 2023 |website=CNN Business |language=en |archive-date=February 8, 2023 |archive-url=https://web.archive.org/web/20230208000306/https://www.cnn.com/videos/business/2023/02/07/cat-chess-bot-mittens-contd-orig-fj.cnn-business |url-status=live }}{{Cite web |last1=Robinson |first1=Joshua |last2=Beaton |first2=Andrew |date=January 18, 2023 |title=The Chess World's New Villain: A Cat Named Mittens |url=https://www.wsj.com/articles/chess-mittens-cat-bot-11674018529 |access-date=January 19, 2023 |website=The Wall Street Journal |language=en-US |archive-date=January 19, 2023 |archive-url=https://web.archive.org/web/20230119001435/https://www.wsj.com/articles/chess-mittens-cat-bot-11674018529 |url-status=live }}{{Cite web |last=Fernandez |first=Manuel |date=January 23, 2023 |title=El ajedrez online tiene un nuevo campeón: un gatito virtual que pone en jaque a maestros y aficionados |url=https://www.elespanol.com/omicrono/software/20230123/ajedrez-online-campeon-gatito-virtual-campeones-aficionados/735926689_0.html |access-date=January 24, 2023 |website=El Español |language=es |archive-date=January 23, 2023 |archive-url=https://web.archive.org/web/20230123190833/https://www.elespanol.com/omicrono/software/20230123/ajedrez-online-campeon-gatito-virtual-campeones-aficionados/735926689_0.html |url-status=live }} Appearing as a kitten,{{Cite news |last=Hörmark |first=Andreas |date=February 1, 2023 |title='Alla vill se Carlsen spela mot katten' |language=sv |work=Svenska Dagbladet |url=https://www.svd.se/a/kEQM4j/chess-coms-servrar-kraschar-pa-grund-av-katten-mittens |access-date=February 14, 2023 |issn=1101-2412 |archive-date=February 5, 2023 |archive-url=https://web.archive.org/web/20230205224013/https://www.svd.se/a/kEQM4j/chess-coms-servrar-kraschar-pa-grund-av-katten-mittens |url-status=live }} Mittens trash talked its opponents with a selection of voice lines: these lines included quotes from J. Robert Oppenheimer, Vincent van Gogh and Friedrich Nietzsche, as well as the 1967 film Le Samouraï.{{Cite web |last=Kelemen |first=Luci |date=January 5, 2023 |title=What is the Mittens chess bot? |url=https://dotesports.com/chess/news/what-is-the-mittens-chess-bot |access-date=January 9, 2023 |website=Dot Esports |language=en-US |archive-date=January 9, 2023 |archive-url=https://web.archive.org/web/20230109203553/https://dotesports.com/chess/news/what-is-the-mittens-chess-bot |url-status=live }} The engine's "personality" was devised by a writing team headed by Sean Becker, and Marija Casic provided the engine's graphics.

Chess.com did not disclose any information about the software running the engine. It may be based on Chess.com's Komodo Dragon 3 engine.{{Cite news |last=Barden |first=Leonard |date=January 9, 2023 |title=Carlsen takes on the young guard on Saturday at the 'chess Wimbledon' |work=Financial Times |url=https://www.ft.com/content/d152fd54-8d56-4988-b42b-9e656dd8adf0 |access-date=January 9, 2023 |archive-date=January 9, 2023 |archive-url=https://web.archive.org/web/20230109121540/https://www.ft.com/content/d152fd54-8d56-4988-b42b-9e656dd8adf0 |url-status=live }} Mittens' strategy was to slowly grind down an opponent, a tactic likened to the playing style of Anatoly Karpov. Becker stated that the design team believed it would be "way more demoralizing and funny" for the engine to play this way. According to Hikaru Nakamura, Mittens sometimes missed the best move (or winning positions).

On Chess.com, Mittens had a rating of one point. However, the engine's playing style and tactics showed that it was stronger than that; Mittens was able to beat or draw against many top human players. In an interview with CNN Business, Whalen stated that the idea behind giving Mittens a rating of one was to surprise its opponents, giving it the upper hand psychologically.

Estimates of Mittens' true rating range from an Elo of 3200 to 3500, because of its ability to beat other engines of around that level. An upper bound of the engine's rating was found after Levy Rozman made Mittens play against Stockfish 15, a 3700 rated engine. Mittens lost the two games that the engines played. The range of Mittens' possible ratings was summarized by Dot Esports, who stated:

{{Block quote|text=It seems like she’s around the 3200–3500 rating range (in Chess.com terms, where the best human players, like Magnus Carlsen and Hikaru Nakamura, sport a 3000–3100 rating in the faster formats), as evidenced by her victories over the site’s otherwise strongest, 3200-rated bots, and her defeat to Stockfish 15, which is currently rated around 3700.}}

File:Nakamura Hikaru (29290269410) (cropped) (cropped).jpg played a match against Mittens that ended in a draw after 166 moves]]

Against human players, Mittens won over 99 percent of the millions of games it played. Chess players such as Hikaru Nakamura, Benjamin Bok, Levy Rozman and Eric Rosen struggled against Mittens; while Rozman and Rosen both lost against the engine, Nakamura and Bok were both able to make a draw.{{Cite web |last=Posnanski |first=Joe |author-link=Joe Posnanski |date=January 9, 2023 |title=Mittens and the End of Art |url=https://joeposnanski.substack.com/p/mittens-and-the-end-of-art |access-date=January 10, 2023 |website=JoeBlogs |language=en |archive-date=January 9, 2023 |archive-url=https://web.archive.org/web/20230109171825/https://joeposnanski.substack.com/p/mittens-and-the-end-of-art |url-status=live }} In particular, Nakamura's game against the engine lasted 166 moves; he was playing as White.{{Cite news |last=Whipple |first=Tom |date=January 23, 2023 |title=Mittens makes mincemeat of grandmasters |language=en |work=The Times |url=https://www.thetimes.com/business-money/technology/article/mittens-makes-mincemeat-of-grandmasters-0t3tcg6cx |access-date=January 24, 2023 |issn=0140-0460 |archive-date=January 23, 2023 |archive-url=https://web.archive.org/web/20230123182328/https://www.thetimes.co.uk/article/mittens-makes-mincemeat-of-grandmasters-0t3tcg6cx |url-status=live }} Bok, Benjamin Finegold and Rozman later went on to win against Mittens, the latter with engine assistance from Stockfish.{{Citation |title=MITTENS VS GM BEN FINEGOLD | date=January 6, 2023 |url=https://www.youtube.com/watch?v=if7ig44gjB4 |access-date=2024-02-17 |language=en}}{{Cite web |last=Yao |first=Deborah |date=January 20, 2023 |title=Meet Mittens, the AI Chess Bot Players Love to Hate |url=https://aibusiness.com/ml/meet-mittens-the-ai-chess-bot-players-love-to-hate |access-date=January 21, 2023 |website=AI Business |language=en |archive-date=January 21, 2023 |archive-url=https://web.archive.org/web/20230121175445/https://aibusiness.com/ml/meet-mittens-the-ai-chess-bot-players-love-to-hate |url-status=live }} Magnus Carlsen publicly refused to play the engine, calling it a "transparent marketing trick" and "a soulless computer".

Against other chess engines, Mittens participated in the Chess.com Computer Chess Championship as a side act. In the competition, Mittens played 150 games against an engine named after the film M3GAN and won overall with a score of 81.5 to 68.5. This equated to 54 percent of the games played. During the event, an estimate of Mittens' rating was made at 3515 points.{{Cite web |title=CCC: M3GAN vs Mittens |url=https://www.chess.com/computer-chess-championship#event=m3gan-vs-mittens |access-date=April 10, 2023 |website=Chess.com |archive-date=November 2, 2018 |archive-url=https://web.archive.org/web/20181102011121/https://www.chess.com/computer-chess-championship#event=m3gan-vs-mittens |url-status=live }}

Mittens went viral in the chess community due to its concept and design: according to an announcement by Chess.com, a combined total of 120 million games were played against the cat engines over the course of January, with around 40 million played against Mittens.{{Cite web |date=February 8, 2023 |title=Server Trouble And The End Of Mittens? |url=https://www.chess.com/article/view/chesscom-update-january-2023 |website=Chess.com}}{{Cite web |title=Mittens – The Chess-Playing Cat That Conquered The Internet! |url=https://www.chess.com/terms/mittens-chess |access-date=April 10, 2023 |website=Chess.com |series=Chess Terms}} The popularity of the engine was helped by the social media exposure created by Chess.com. This included creating an official Twitter account to promote the engine.{{Cite web |last=Zulkiflee |first=Sarah |date=February 2, 2023 |title=Goodbye Mittens. Chess.com removes the viral cat bot from its site |url=https://esports.gg/news/chess/mittens-removed-from-chess-com/ |access-date=February 2, 2023 |website=Esports.gg |language=en |archive-date=February 2, 2023 |archive-url=https://web.archive.org/web/20230202182440/https://esports.gg/news/chess/mittens-removed-from-chess-com/ |url-status=live }} Chess streamers like Rozman and Nakamura helped cultivate this by creating content around the engine.{{Cite web |last=Zulkiflee |first=Sarah |date=January 9, 2023 |title=Why is the Chess.com cat bot, Mittens, so popular? |url=https://esports.gg/news/gaming/why-is-the-chess-com-cat-bot-mittens-so-popular/ |access-date=January 16, 2023 |website=Esports.gg |language=en |archive-date=January 16, 2023 |archive-url=https://web.archive.org/web/20230116202909/https://esports.gg/news/gaming/why-is-the-chess-com-cat-bot-mittens-so-popular/ |url-status=live }} A video by Nakamura entitled "Mittens the chess bot will make you quit chess" gained over 3.5 million views on YouTube.

On January 11, Chess.com reported issues with database scalability due to record levels of traffic: 40 percent more games had been played on Chess.com in January 2023 than any other month since the website's release.{{Cite news |last= |first= |date=January 24, 2023 |title=Mittens, el gatito virtual que está derrotando a los campeones del ajedrez |url=https://elcomercio.pe/tecnologia/actualidad/mittens-el-gatito-virtual-que-esta-derrotando-a-los-campeones-del-ajedrez-espana-mexico-estados-unidos-noticia/ |access-date=January 25, 2023 |website=El Comercio |language=es |archive-date=January 24, 2023 |archive-url=https://web.archive.org/web/20230124205739/https://elcomercio.pe/tecnologia/actualidad/mittens-el-gatito-virtual-que-esta-derrotando-a-los-campeones-del-ajedrez-espana-mexico-estados-unidos-noticia/ |url-status=live }} According to The Wall Street Journal, the popularity spike was more than the similar surge following the release of Netflix's The Queen's Gambit. The popularity of Mittens was cited by Chess.com as a reason for this instability.{{Efn|Other suggested reasons for the website's instability included a chess boxing tournament hosted by the streamer Ludwig Ahgren and other chess content created by Levy Rozman.{{Cite web |last=Bellingham |first=Hope |date=January 11, 2023 |title=Adorable cat bot credited with a huge spike in players for leading chess website |url=https://www.gamesradar.com/adorable-cat-bot-credited-with-a-huge-spike-in-players-for-leading-chess-website/ |access-date=January 16, 2023 |website=GamesRadar |language=en |archive-date=January 16, 2023 |archive-url=https://web.archive.org/web/20230116083733/https://www.gamesradar.com/adorable-cat-bot-credited-with-a-huge-spike-in-players-for-leading-chess-website/ |url-status=live }} |name=Instability reasons|group=lower-alpha}} The problems continued throughout January;{{Cite magazine |last=Hoover |first=Amanda |date=January 25, 2023 |title=Celebrities, TikTok, and a Cat Bot Are Crashing Chess.com |url=https://www.wired.com/story/chess-dot-com-tiktok-mittens-scandal/ |magazine=Wired |language=en-US |issn=1059-1028 |access-date=January 25, 2023 |archive-date=January 25, 2023 |archive-url=https://web.archive.org/web/20230125120633/http://www.wired.com/story/chess-dot-com-tiktok-mittens-scandal/ |url-status=live }} Chess.com stated that they would have to upgrade their servers and invest more in cloud computing to solve the problems caused by the website's popularity surge.{{Cite news |last=Stanton |first=Rich |date=January 24, 2023 |title='Honestly, this sucks,' says Chess.com as its servers can't keep up with Chess's explosive popularity |language=en |work=PC Gamer |url=https://www.pcgamer.com/honestly-this-sucks-says-chesscom-as-its-servers-cant-keep-up-with-chesss-explosive-popularity/ |access-date=January 24, 2023 |archive-date=January 24, 2023 |archive-url=https://web.archive.org/web/20230124161622/https://www.pcgamer.com/honestly-this-sucks-says-chesscom-as-its-servers-cant-keep-up-with-chesss-explosive-popularity/ |url-status=live }}

On February 1, 2023, Mittens and the other cat engines were removed from the computer section of Chess.com. They were replaced with five new engines themed around artificial intelligence. A tweet was posted on the Mittens's Twitter account after the engine's removal, reading "This is just the beginning. Goodbye for now."

{{Notelist|group=lower-alpha}}

These sources are published by Chess.com, and are indicated in this article by a double dagger (‡):

{{Reflist|group=‡}}

{{Reflist}}

• {{Twitter|id=MittensChess}}
• [https://my.hamilton.edu/news/story/chess-mittens-cat-bot-will-whalen Hamilton College interview with Will Whalen]

{{Chess}}

Category:Chess engines

Category:Internet properties established in 2023

Category:2023 in chess

Category:Free web software

Category:2023 software

Category:Applied machine learning

Category:Fictional cats

Category:Chess.com