A type of U Geminorum star that exhibits distinct, well-defined outbursts, with an amplitude of 2–6 mag.; abbr. UGSS. The rise time is 1–2 days, with a rather longer decline. The mean interval between outbursts ranges between ten and thousands of days. There are variations in the amplitude, duration, and shape of individual maxima. Although most stars have distinct short and long outbursts, the latter bear little resemblance to the supermaxima of an SU Ursae Majoris star.