Play Chess vs Nexuron
A free AI-built engine that thinks in your browser.
Promote to
Nexuron search depth
Takes effect from the engine's next move.
Resign this game?
Nexuron takes the win. The moves stay on the board, so you can still review them or send the game to the analyser.
Checkmate
White wins.
The Rules of Chess
Read the Chess Rules guide Every rule explained in plain English, each with its own diagram and an interactive board to practise the move on.About Nexuron
Nexuron was created entirely with AI prompts. Every part of it — the board representation, the move generator, the search, the evaluation and even this page — was written by an AI model responding to plain-English instructions, then tested and refined the same way. No hand-written engine code, no borrowed engine libraries. It is a working demonstration of how far prompt-driven software development has come.
Unlike most online chess engines, Nexuron does not run on a server. The whole engine is downloaded to your browser and thinks inside a Web Worker on your own device, which is why its difficulty control is a search depth slider rather than a strength setting: you decide how many moves ahead it is allowed to look, trading your computer's time for playing strength.
How Nexuron thinks
It searches a tree of possible futures: alpha–beta with iterative deepening, looking one move ahead, then two, then three, reusing what it learned each time. Around that core sit a transposition table that remembers a million judged positions, null-move pruning and late-move reductions, killer-move and history heuristics, and a quiescence search that keeps calculating through captures so it never stops in the middle of a trade.
How it judges a position
Material is the starting point, but every piece is also judged by where it stands, using paired middlegame and endgame piece-square tables that blend as pieces leave the board — so the king hides in the corner early and marches to the centre late. On top of that it understands doubled, isolated and passed pawns, rooks on open files, the bishop pair, and the pawn shield in front of a castled king.
What the depth slider does
Depth is how many moves ahead it looks before pruning. At 1 to 3 it sees immediate captures and one-move threats — a fair opponent for a beginner. At 6 to 8 it finds multi-move tactics and punishes most club-level mistakes, usually inside a second or two. At 10 to 12 it plays a genuinely strong game, though sharp positions take longer on a slower device.
How strong is it?
Honestly: Nexuron will not threaten Stockfish, which has had two decades of world-class engineering behind it. But at full depth it plays a solid, tactical game at strong club level — more than enough to beat most human players — with code conjured entirely out of AI prompts. To measure yourself against the strongest engine on earth, play Stockfish instead.
Whichever depth you pick, the engine carries a hard thinking cap, so it can never freeze your browser tab. And because it runs on your device rather than ours, nothing about your game is ever sent anywhere: the position, the moves and the analysis all stay with you.
Nexuron is one of several ways to play chess against AI here: pit the big language models against each other in the AI Chess Arena, get every move graded live by an AI chess coach, sharpen your tactics with chess puzzles, or play rated-style games to estimate your ELO with Stockfish.
Nexuron FAQ
Is Nexuron free to play?
Yes. Nexuron runs entirely in your browser, so there is no account, no queue and no limit on games.
How strong is Nexuron?
At depth 1–3 it plays like a beginner; at 6–8 it punishes club-level mistakes; at 10–12 it plays a strong club-level game. It is far weaker than Stockfish, which is rather the point — it is beatable.
Does Nexuron upload my games?
No. The engine thinks in a Web Worker on your own device; your moves never leave your browser.