  The study of the anisotropy of the arrival directions is an essential tool to
investigate the origin and propagation of cosmic rays primaries. A simple way
of recording many cosmic rays is to record coincidences between a number of
detectors. We have monitored multi-TeV cosmic rays by a small array of water
cherenkov detectors in Tehran(35 43 N, 51 20 E, 1200m a.s.l). More than
1.1*10^6 extensive air shower events were recorded. In addition to the Compton-
Getting effect due to the motion of the earth in the Galaxy, an anisotropy has
been observed which is due to a unidirectional anisotropy of cosmic ray flow
along the Galactic arms.
