Practice board

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.

The engine here works the other way round. It never grades a move you have played; press Ask the engine and it shows the five moves it would consider in the position now on the board, with what each is worth. It starts when you press it and stops when you press it again.

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.