A chess problem is an artificial construction, not part of the game, but using a board and pieces. It is a separate intellectual activity. Chess problems have a history as long as the game itself, and their own terminology. The Arabs (9th/10th centuries) used specially composed positions ("mansurbat") as teaching devices; the idea of specifying a set number of moves to mate is European. Problem solving tournaments are held, and there is a World Championship for problem solvers. There are also international prizes for problem composers.