  We give an overview of circumstellar interaction in young Type II supernovae,
as seen through the eyes of very-long-baseline interferometry (VLBI)
observations. The resolution attained by such observations (best than 1 mas) is
a powerful tool to probe the interaction that takes place after a supernova
goes off. The direct imaging of a supernova permits, in principle, to estimate
the deceleration of its expansion, and to obtain information on the eject and
circumstellar density profiles, as well as estimates of the magnetic field
intensity and relativistic particle energy density in the supernova.
Unfortunately, only a handful of radio supernovae are close and bright enough
as to permit their study with VLBI. We present results from our high-resolution
observations of the nearby Type II radio supernovae SN1986J and SN2001gd.
