  The WL-dimension of a graph X is the smallest positive integer m such that
the m-dimensional Weisfeiler-Leman algorithm correctly tests the isomorphism
between X and any other graph. It is proved that the WL-dimension of any
circulant graph of prime power order is at most 3, and this bound cannot be
reduced. The proof is based on using theories of coherent configurations and
Cayley schemes over a cyclic group.
