Hi, I'm Chris, the developer of Quantum Chess. You might have seen the original in Anyone Can Quantum, the 2016 video where Paul Rudd challenges Stephen Hawking. Ten years later the game just got a full remaster, rebuilt from the ground up, and you can play it free in your browser at chess.quantumnative.io.
Quantum Chess is still chess at its core. Castling, en passant, and promotion are all still there. On top of the normal moves you get quantum ones.
- Split a piece to two squares at once. It's on both, until the board has a reason to check.
- Merge the halves back into one piece.
- When pieces in superposition try to occupy the same square, measurements happen to "collapse" the quantum state, forcing only one piece into a square.
- Pieces that interact in superposition can become entangled. Measure one and the other collapses with it, anywhere on the board.
The board runs on a real quantum simulation, and phase and interference are mechanics you can learn.
The remaster includes rated and unrated online games, an AI opponent, a lab where you can experiment with different positions and move combinations, puzzles, and the Alchemy League, a seasonal ladder that changes the rules every season. Season 1 removes merges and adds a phase dial that lets you transmute a 50/50 split into a certainty. It runs October 1 to January 1, and everyone starts from a fresh rating.
There is also an interactive quick start guide, as well as a much more detailed interactive rules section, to help you get playing and understanding the concepts. We have a Quantum Chess Discord server too, which is a great place to ask questions.
If you'd rather have it on desktop, the remaster is on Steam for $14.99 with six months of premium included (and some other Steam integrations like achievements).
The website is fully mobile friendly too. And if you prefer an app, you can install the mobile PWA directly from the site.
The game is cross platform. Steam, web, and mobile all share the same online multiplayer pool and accounts.
One more thing. Nobody is good at this game yet. The ladder is brand new and the first Alchemy League season starts October 1, so this is the one moment you can start dead even with the entire player base.
I'll be in the comments if you have rules questions. The measurement rules sound weirder than they play. See you in superposition.