  The Kerov--Kirillov--Reshetikhin (KKR) bijection gives one to one
correspondences between the set of highest paths and the set of rigged
configurations. In this paper, we give a crystal theoretic reformulation of the
KKR map from the paths to rigged configurations, using the combinatorial R and
energy functions. This formalism provides tool for analysis of the periodic
box-ball systems.
