  The flow of kaons, i.e., the average kaon transverse momentum as a function
of rapidity, and the associated flow parameter in heavy-ion collisions at
SIS/GSI energies is investigated in the relativistic transport model. It is
found that the pattern of kaon flow at the final stage is sensitive to the kaon
potential used in the model and is thus a useful probe of the kaon potential in
a nuclear medium.
