Don’t play the engine move
Copy Stockfish’s first choice and its rating goes up 100. Play something else and nothing happens. The engine gets harder when you cheat the rule.
Don’t play the engine move
Copy Stockfish’s first choice and its rating goes up 100. Play something else and nothing happens. The engine gets harder when you cheat the rule.
Your move
How it works
- Set Stockfish’s strength with the slider.
- Add rules to make Stockfish stronger or weaker as you play.
- Undo takes back your move and Stockfish’s reply.
- After the game, you can review every move.
Your own rules
A rule is a trigger, an effect and an amount: engine top move, any other move, capture, non-capture, a blunder (graded as the review grades it), check or promotion, set to make Stockfish stronger or weaker. Named modes live under Game modes, with the rules already on; /play is the blank customiser.
The engine follows you
Stockfish’s rating goes from 0 to 3190. In a “don’t” mode, breaking the rule makes Stockfish stronger. In a “reward” mode, doing the thing makes it weaker. With no rules, it’s a normal game.
Summary, link and review
When a game ends you see how you did — blunders, mistakes and the costliest move — and you can open it as a full game review. Every finished game gets its own link. To start from a position instead, use the sandbox board.