Everything that isn’t a rule of the game itself.
Yes. The full game — every rule, the tutorial, local two-player, online 1v1 matchmaking, the standard bot roster, and the daily puzzle — is free to play in your browser, no download or install. Ads and the optional Premium tier keep the servers on.
It helps, but it isn’t required. If you know how the six classical pieces move, the interactive tutorial teaches everything else: it plays a full guided game against you, introducing superposition, zaps, heals, captures, castling, and promotion one move at a time. You can replay it any time from the rules menu.
Yes. The game runs in any modern mobile or desktop browser, with a touch layout for small screens. There is no app to install.
No. Despite the quantum theming, every rule is fully deterministic — zap targets, collapse results, heal spillovers, and the conservation solver always resolve the same way from the same position. Nothing is decided by dice you can’t see.
Every day there is one puzzle, the same for everyone, mined from a real game at the moment one precise move mattered most. You are shown the position and asked to find the best move. Your answer is graded against the engine’s own ranked list of every legal move in the position.
Grades run from a star (you found the engine’s top move) through green, yellow, orange, and red, down to a skull. The grade reflects both how your move ranked among all legal moves and how much evaluation it gave away — a move that keeps a winning position winning still scores well even when it isn’t the single best choice, while a move that throws the position away earns the skull no matter how natural it looked.
Solving the daily puzzle records your result for that calendar day and feeds your streak — consecutive days played. After you finish, you get a spoiler-free, emoji-grade share card (in the spirit of Wordle results) you can paste anywhere. Skipping a day breaks the streak; watching the solution without playing records nothing.
No. You can play every mode anonymously. An optional free account earns you a rating from online games, keeps your recent game history (up to 10 saved games on the free tier), and syncs your daily-puzzle streak.
Online 1v1 games between signed-in players adjust an Elo-style rating after each result. Bot games and local games never affect your rating, so practice is always free of consequence.
Premium is $3/month and exists because Quantum Chess is built and run by one person. It removes ads and adds game review with engine moves, unlimited saved games, premium bots to battle, a custom profile picture and tagline, and the full character roster with 32 more taglines and sayings. Subscriptions are handled by Stripe and can be cancelled any time from your account.
Not a subscription person? A one-time $3 tip buys a year with no ads plus one engine game review per day. Tips stack — tip twice and you have two years.
After any finished game, the review board replays it move by move with an evaluation graph, marking the moments the game swung and showing the engine’s preferred move where yours went astray. It is the fastest way to find out where your King count quietly collapsed.
Every bot is a fictional parody mashup of a deceased scientist and a deceased chess legend. Their portraits, personalities, sayings, and ratings are invented; none depicts a real person, and no affiliation or endorsement is implied.
Feedback, bug reports, and hellos all go to contact@quantumchess.ninja. Bug reports with the move list attached (copyable from the in-game history panel) get fixed fastest.
The complete rulebook covers every rule on one page, and the strategy guide covers what to do with them. In the game itself, the tutorial and the paginated rulebook live behind the book icon in the side menu.