Play the Chain

Stockfish, compiled from C++ with icpp-pro, running inside an Internet Computer canister.
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What is Stockfish? The strongest open-source chess engine in the world, and for years the reigning computer chess champion. Grandmasters use it to analyse their games; no human has a realistic chance against it at full strength. It's over 12,000 lines of performance-tuned C++. What's new here: that whole engine was compiled to WebAssembly and runs inside a smart contract (a canister on the Internet Computer). Every move it plays is computed by 13 independent machines that must agree on it, with no server behind it.

Start a game. The canister will referee it.
Moves · tap one to replay it and see its receipt
⛓ On-chain view

What happens when you move

Left: what it means. Right: what actually runs, for the technically curious.
⛽ Fuel the chainall games & cycles →

Free for everyone, thanks to one shared fuel tank

Every move takes a little computing power. One shared tank pays for everybody, so there are no ads and no sign-up. If it runs dry, the game pauses. Add a little ICP to keep it going for everyone.
In the tank
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  1. Send ICP (0.12 or more) from any ICP wallet, like your funnAI wallet or the NNS app, to:
    ne5l7-xiaaa-aaaaj-qsm3q-cai
    Sending from an exchange? Exchanges want an account ID. Use this one:
    460d1214503541468865ef7728ed17cf6e232585e6898a8d1626230ffa8e2cc7
  2. Tap Top up. Your ICP goes into the tank in a few seconds.
How it works
The game runs on the Internet Computer, where computing is paid in cycles. When you tap Top up, Play the Chain buys cycles with your ICP from funnAI GameState, which delivers them straight to the game.

Nothing here runs on a server. The page, the rules and the engine all live in one canister: it checks your move, runs a single-threaded Stockfish 11 search inside the 40B-instruction limit of one message, and writes both moves to its stable memory. The game record can't be edited afterwards.