Mittens?

Introduction

In January 1, 2023 Mittens was released by chess.com as part of the New Year event on chess.com. The engine became viral in the chess community due to the content made by chess streamers and a social media marketing campaign, This later contribute to record levels of traffic to the Chess.com website and causing issues with database scalability. 

How it works

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. Mitten's strategy was to slowly grind down an opponent, a tactic like the playing style of Anatoly Karpov. Mittens sometimes missed the best move.

Voice lines 

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. 

Rating

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. The range of Mitten's possible ratings was summarized by Dot Esports, who stated:

"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."

Impact

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. The popularity of the engine was helped by the social media exposure created by Chess.com.

Thank you for spending your time on this!

- @thinhdoduy