What's a premove?
In fast chess, players premove — queueing a reply before the opponent
has moved, so it fires the instant their clock starts. With premoving on, the bot asks
Maia what you're most likely to play, if it assesses that your reply is forced, it applies that supposedly forced move, chooses its own next move based on that position — then commits to it.
Which engine answers?
Both halves of the guess come from Maia 3, not Stockfish. Maia is
trained on human games, so it predicts what a player would do rather than what is
objectively best — which is what makes a premove worth trapping. It runs twice: once on
the current position to guess your reply, and again on the resulting position to choose
the bot's own answer.
Maia is asked at the bot's own rating band, not yours. A human premoving is
also guessing from their own understanding, so a strong bot anticipates a weaker
opponent imperfectly — exactly as a strong human would.
Premoving is inert until the Maia 3 model has been downloaded; the bot simply plays
normally instead. Download it in the vs Bot panel.
What's a premove trap?
A premove saves seconds, but commits blindly. A premove trap is the
counter: work out what your opponent has queued, then play the move that makes their
committed reply the wrong one.
The premove doesn't react to you. It fires whatever you played, so the bot can walk
past free material — playing its queued move elsewhere while a piece it would normally
capture sits there untouched. Squares that look unsafe often aren't, once you notice the
defender is busy playing something it decided on before you moved.
If your move makes the premove illegal — pinning the piece, capturing it, or
moving its target away — the premove is busted instead, and the bot must think from
scratch, burning the Busted-premove delay on its own clock.
See it played
Worked examples are easier to learn from than descriptions:
Raise Premove rate toward 100% and lower
Min confidence in the premove controls to make the bot premove
more often and more exploitably.