The object of the game is to capture the other player's king. This capture is never actually completed, but once a king is under attack and unable to avoid capture, it is said to be checkmated and the game is over.
A move consists of placing one piece on a different square, following the rules of movement for that piece. A player can take an opponent's piece by moving one of his or her own pieces to the square that contains an opponent's piece. The opponent's piece is removed from the board and is out of play for the rest of the game.
The pieces can be moved by dragging them with the mouse on their initial square and dropping them to their destination field. For special moves the same applies