The normal form games studied today are one in which both players take actions simultaneously. A sequential game, like chess, can in principle be made into a normal form game, but each pure strategy for white would need to be a complete specification of the moves white would make in each possible board position that could be reached by prior moves of white and black playing in some way. The number of pure strategies for white would need to exceed the Shannon number, which is the number of different games of chess that can be played. It is thought to be about $10^{120}$.