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Explain shows on the board why the last move is good or bad. Press the button between the arrows under the board, or the E key.

The engine looks at the position before and after the move and draws arrows:

• red arrows: material is about to fall, and the pieces that are lost are ringed;
• green arrows: your side's ideas, the moves that make the evaluation;
• blue arrows: the other side's moves — the reply that makes the difference when nothing is lost yet, or its plan; your side is the one you play in training, otherwise the one at the bottom of the board;
• dashed red arrows: a threat, a piece left attacked — "5.Qxf3 attacks the rook on a8", or the one your move did not answer, "5…Qh4+ leaves the rook on a8 attacked: 7.Qxa8";
• a dashed green arrow: the better move you had instead. When it moves the same piece you moved — so the square it leaves is empty now, that piece having gone elsewhere — the piece is drawn small and faint where it should have landed.

A forced mate is played out on the board, inside a red frame. The Engine panel says it in words, for example “Blunder (+0.3 → −2.9). Black wins a knight”.

Explain reads the analysis running in the Engine panel: the explanation appears as soon as the engine has searched deep enough, and gets sharper as it goes deeper — the arrows change only when a new line holds for a while. The move is judged against the position before it: if that was never analysed (you came straight to the move, or reopened Pragma Chess on it), the engine looks at it first, for a moment, and then goes on with the position on the board. Until the first answer the border of the board breathes; it turns blue when the explanation is there. Explain is about one move: going to another move turns it off, and you ask again. Closed with Explain on, Pragma Chess opens with it on, on the same move.

Edit ▸ Copy ▸ Explanation copies the text.