  We present evidence for rotational modulation of X-ray flares by an analysis
of four outbursts on late-type stars. Three of these flares have been observed
on T Tauri Stars and one on Algol.
  The structure of the X-ray lightcurves observed in this selection of flare
events is untypical in that the maximum emission extends over several hours
producing a round hump in the lightcurve instead of a sharp peak. We explain
this deviation from the standard shape of a flare lightcurve as the result of a
flare erupting on the back side of the star and gradually moving into the line
of sight due to the star's rotation. An estimate for the decay timescale and
the size of the X-ray emitting volume is derived. Spectral information supports
our proposition that changes of the visible volume are responsible for the
observed time development of these flares.
