Board
Practice board
Move both sides by hand. Nothing here is analysed, graded, saved or sent anywhere — it is a board, and it does not have an opinion.
White to play. Drag a piece, or tap it and then its square.
What this is for
Setting a position up with your hands, showing somebody how a mate works, playing a line out to see where it goes — the things a real board is for, and the things an analysis screen is bad at, because an analysis screen is always busy telling you what a move was worth.
When you do want that, it is the rest of the site: import a game from chess.com or paste a PGN and Stockfish grades every move in your own browser. To drill an opening rather than wander, the opening pages each have a board that plays the other side for you and stops you when you leave the line.