Because of instrumental sensitivity limits and stellar distances, the
types of x-ray flares observable on stars have been intrinsically much
more energetic than those on the sun. Such enormous events are a usef
ul extrapolation of the solar phenomenon if the underlying assumption
is correct that they form a continuous sequence involving similar phys
ical processes as on the sun. The Advanced Satellite for Cosmology and
Astrophysics (ASCA), with its greater sensitivity and high-energy res
ponse, is now able to test this hypothesis. Direct comparison with sol
ar flares measured the x-ray-monitoring Geostationary Operational Envi
ronmental Satellites (GOES) is possible. The detection of flares on Pr
oxima Centauri that correspond to GOES M-class events on the sun are r
eported.