Chess is Finite.

I've been told that there are an infinite number of moves in chess,

how is that consivable? Granted the number may be higher than the amount

of different suduko puzzles that can be created but he possibilities can not

be endless. To open white can advance to 1 of 20 squares then black can

do the same, which would be 20 squared right? I'm an acontant don't expect

me to be good @ math. Any way 20x20 plus.......there has to be a formula!