Playable system · CHESS/64

A clean board,
and the reason
behind the move.

Play a full game against an engine that lives entirely in this page — or put the engine in Record mode, type in the moves of a game happening on a real board, and read what it thinks of each one.

Open the board What Record mode is for

Board · engine · record

Chess
Lab

Click a piece to see its legal squares, then click one. Everything below is a setting; nothing is sent anywhere.

Mode

Play answers your move. Record never moves a piece: it is for following a game on a physical board. Enter each move as it is played, for either side, and the engine analyses the position it produced.

Your colour

Changing colour starts a new game.

Opponent

Each level sets a thinking budget and how much noise the engine tolerates in its own choices. These are settings, not ratings, and this interface does not translate them into human playing strength.

Game record00

One line per full move, as it would be written on a scoresheet.

White to move.

The board needs JavaScript. The rules, the evaluation and the search are all plain modules that run in this tab — there is no server to fall back to, and nothing to log in to.

0.0

White pieces taken

Black pieces taken

Analysis

not run yet

What the engine sees

Nothing has been searched yet. Make a move, or ask for an analysis without one.

Candidate lines

The lines the engine prefers appear here, best first, with the score it gave each one.

Reasons

Every bullet names the computation that produced it — a search score, a static exchange, one evaluation term. A claim with nothing behind it is not shown.

Last move

not reviewed

Once a move has been played by hand, this compares it with the move the engine preferred, and says how much the difference was worth.

Enter a move

Written the way a scoresheet is written, and forgiving about it: plain coordinates work, and the capture and check marks are optional.

Position

Record mode follows a real game.

Switch to Record and the engine stops playing. Enter the moves as they happen at the board, for whichever side just moved, and after each one you get a fresh evaluation, the candidate lines, and a verdict on the move that was actually made. It will not touch a piece on its own.

Both modes share one game.

Position, move list, undo and repetition counts survive the switch. Start a game against the engine, move to Record when a friend sits down, and go back — nothing is rebuilt behind your back.

Analysis has to cite itself.

Each bullet in the panel carries the calculation that produced it. If no named computation supports a sentence, the page would rather say nothing than narrate.

A clean board,and the reasonbehind the move.

Record mode follows a real game.

Both modes share one game.

Analysis has to cite itself.

A clean board,
and the reason
behind the move.