Loses 300 Elo when you check

Every check you give drops Stockfish’s rating by 300. Check often enough and it drops to beginner strength.

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.

Loses 300 Elo when you check

Every check you give drops Stockfish’s rating by 300. Check often enough and it drops to beginner strength.

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.