Touch-move rule the player touches his rook at the same time as touching the king, he must castle with that rook if it is legal to do so. If the player completes a two-square king move without touching a rook, the player must move the correct rook accordingly if castling on that side is legal. Otherwise, the move must be withdrawn and another king move made. When a pawn is moved to its eighth , once the player takes his hand off the pawn, a different move of the pawn can no longer be substituted. However, the move is not complete until
First-move advantage in chess additional pieces. Fischer advocated Fischerandom Chess, another chess variant, in which the initial position of the pieces is determined at random. Today some of the opening variations have been analyzed so deeply that they are often used as . For example, at the highest levels, Black often uses the Marshall Attack in the Ruy Lopez, a line where Black sacrifices a pawn for strong attacking chances, to obtain an endgame where Black is still a pawn down but is able to draw with correct play. In 2007, GMs Kiril Georgiev and Atanas Kolev asserted that much the same was true