Many people must have played chess before. No matter which kind of chess we are playing, we always try our best to find a way to beat our opponent. It is thus natural to think whether there is a way that one must win the game. Intuitively it cannot exist -- who can guarantee a win in such complicated games as chess? However, game theory tells us that such a way does exist if no tie is possible. To learn more, see http://db.math.ust.hk/resource_sharing/others/sc_cchess.pdf.