Othello, for stakes — and the contract itself is the referee: every placement is verified on-chain (it must flip at least one disc), every bracketed run is flipped by the contract, and when both players pass, the contract counts the discs and pays the majority instantly. No disputes possible. ⚫ moves first; each move lands in the next block (~6–12 s). Stalling can't steal — a silent opponent only voids the game and refunds you.
Your key never touches this page — signing happens in your wallet at get.nadochain.com, then you bounce back.
Every move is a signed transaction bound to its exact turn number — replays and stale retries bounce off. The contract enforces whose turn it is, validates the placement (it must bracket and flip at least one enemy disc — the real Othello rule) and performs every flip itself. Two consecutive passes make the contract count the board and pay the majority in the same instant; an equal count refunds both stakes. If your opponent walks away, the move clock (~30 min) lets anyone refund the game — stalling only ever voids, never wins.
Same game vs the computer: nothing touches the chain, no wallet needed. For real stakes, use the game above.