The heels of the chess world have included Soviet grandmasters, alleged cheaters, and faceless supercomputers. But the game’s latest villain is a fearsome genius who quotes French cinema and has played millions of games in just a couple of weeks.
She also happens to be a mean cat.
Mittens—or technically the chess bot known as Mittens—might look cute. Her listed chess rating of a single point seems innocuous. But her play over the past few weeks, which has bedeviled regular pawn-pushers, grandmasters, and champions who could play for the world title, is downright terrifying. And as it turns out, people are gluttons for punishment.
Since Chess.com introduced this bot with the avatar of a cuddly, big-eyed kitten on Jan. 1, the obsession with playing her has been astonishing. Mittens has crashed the website through its sheer popularity and helped drive more people to play chess than even “The Queen’s Gambit.” Chess.com has averaged 27.5 million games played per day in January and is on track for more than 850 million games this month—40% more than any month in the company’s history. A video that American grandmaster Hikaru Nakamura posted to YouTube titled “Mittens The Chess Bot Will Make You Quit Chess” has already racked up more than three million views.
“This bot is a psycho,” the streamer and International Master Levy Rozman tweeted after a vicious checkmate this month. A day later, he added, “The chess world has to unite against Mittens.” He was joking, mostly.
Mittens is a meme, a piece of artificial intelligence and a super grandmaster who also happens to reflect the broader evolution in modern chess. The game is no longer old, stuffy and dominated by theoretical conversations about different lines of a d5 opening. It’s young, buzzy and proof that cats still rule the internet.
The past few months have seen yet another surge in the worldwide appeal of chess. The viral image from the World Cup was a Louis Vuitton advertisement showing Cristiano Ronaldo and Lionel Messi poring over a board. The picture that summed up the college football national championship was of a TCU fan playing chess on her phone in the stadium while the Horned Frogs got demolished by Georgia. When Slovenian NBA superstar Luka Doncic was asked for his thoughts about Elon Musk’s takeover of Twitter, he shrugged it off and said he uses his phone to play chess.
None of those moments have driven people to virtual chess boards quite like a cat named Mittens who likes to taunt her opponents while she destroys them.
“I am inevitable. I am forever. Meow. Hehehehe,” Mittens tells her opponents in the chat function of games.
Chess.com, the popular platform where both grandmasters and millions of everyday chess lovers play, has a number of bots ranging in skill level and styles for users to challenge. Some are designed to play poorly and be beatable even by a crummy player. Others, in an age when the computers dominate humans, can topple the chess elite.
This particular bot was the brainchild of a Hamilton College student named Will Whalen who moonlights as a creative strategy lead. He had a crazy idea. What if they put an incredibly strong bot behind some devastatingly cute eyes?
“Then Mittens was born,” Whalen says.
But Mittens didn’t become a brutal troll until a Chess.com writer named Sean Becker led a team that developed Mittens’s personality to become the evil genius tormenting chess players everywhere. Part of why Mittens has become such a notorious villain is because she acts like one.
Mittens doesn’t purr. She references ominous lines from Robert Oppenheimer, Van Gogh, and even a 1960s Franco-Italian film called “Le Samourai.”
“Meow. Gaze into the long abyss. Hehehehe,” Mittens says, quoting German philosopher Friedrich Nietzsche.
Even her approach to the game is menacing. Mittens is designed to be skillful enough to beat the best chess players on the planet but uses particularly grueling tactics. Becker thought it would be “way more demoralizing and funny” if, instead of simply smashing opponents, Mittens grinded down opponents through painstaking positional battles, similar to the tactics Russian grandmaster Anatoly Karpov used to become world champion.
It hasn’t been difficult for Becker to see the reactions to his masterpiece. Nakamura, who could manage only a draw against Mittens, bluntly said in a video, “This cat is extremely patient, which is kind of annoying. I’m not going to lie.”
Becker has also seen it when he rides the subway and notices someone on their phone getting crushed by Mittens.
“You can see their eyes be kind of afraid,” Becker says.
Getting absolutely creamed by Mittens might get old. But her surprising popularity speaks to an underlying current in the chess world as freshly minted fans flow in: People are endlessly curious about new ways to engage with the ancient game. Facing novelty bots is just one of them. There has also been a new wave of interest in previously obscure chess variants.
Chess960, for instance, is a version of the game where all the non-pawn pieces are lined up in random order on the back rank. Also known as Fischer Random, for its inventor Bobby Fischer, it has gained traction among elite players as a high-purity test of chess skill and vision, because the random setup makes openings nearly impossible to prepare ahead of time.
In an unprecedented move, chess world governing body FIDE recognized Chess960 and gave it a world championship in 2019. The tournament was closely watched in 2022 when the final featured two of the best players on the planet: Nakamura and Ian Nepomniachtchi, the runner-up at the 2021 world championship of normal chess. (World champion Magnus Carlsen finished third.)
Other variants include: “Fog of War,” where players have a limited view of their opponents’ pieces; “Bughouse Chess,” which is played across two boards with captured pieces potentially moving from one to the other; and “Three Check,” where the objective is simply to put the opposing king in check three times.
The wackiest of all is the chess variant known as Duck Chess. It looks mostly like regular chess—64 squares and 32 pieces. But it also has one rubber ducky on the board.
After every move in Duck Chess, the player moves the titular object to a new square of the board where it blocks pieces in its path. Good luck moving your bishop when there’s a duck squatting on its diagonal.
There are also other cat bots. One is Mr. Grumpers. Another is Catspurrov, which bears a curious resemblance to former world champion Garry Kasparov. None have become a sensation quite like the chess terrorist called Mittens.
“While I still think chess is a symbol of the highest level of strategic thinking,” said Chess.com chief chess officer Danny Rensch, “it’s also a game that is just incredibly fun and enjoyable.”
Just not when you play Mittens.
Write to Andrew Beaton at andrew.beaton@wsj.com and Joshua Robinson at Joshua.Robinson@wsj.com