Analysis board

Chesspedition's analysis board is a free chess board where you move the pieces yourself and Stockfish 19 evaluates every position in your browser. It shows up to five engine lines with their depth, keeps your side lines, and reads and writes FEN and PGN. There are no ads, no daily limit and no sign-up.

How to use it

  1. Drag a piece, or click it and then its square. Only legal moves can be made; a pawn reaching the last rank asks which piece you want.
  2. Read the engine's lines on the right. The number in front of each line is the evaluation in pawns from White's side; M3 means mate in three.
  3. Go back with the arrow keys and play a different move to start a side line. "Make main line" and "Delete from here" tidy the move list.
  4. Copy the position (FEN) or the whole game with its side lines (PGN) with the two copy keys.

Questions

Which engine does the analysis board use?
Stockfish 19, running in your own browser as a separate program. It uses several processor threads when your browser allows it, and one thread otherwise. Nothing about your position is sent to a server.
How do I analyse a position from a diagram or a book?
Paste its FEN into the box under the move list and press Load, or set the pieces up in the board editor and open the position from there.
Can I analyse a whole game?
Yes. Paste the PGN and press Load. The game appears as a move list; click any move to see the engine's lines for that position, and play a different move to start a side line.
How deep does the engine search?
It keeps searching the position on screen until it reaches depth 30, and shows the depth it has reached as it goes. Moving to another position starts a new search.
Is it free?
Yes. The analysis board is free, without ads and without a daily limit.