A form of dwarf nova with an extremely long outburst period, comparable with that of a recurrent nova (i.e. decades). WZ Sagittae itself erupted in 1913, 1946, 1978, and 2001. Small-amplitude variations (less than 0.3 mag.) occur between the major eruptions, and Algol-like eclipses are sometimes visible. The outbursts resemble those of an SU Ursae Majoris star with superhumps, and these systems are now regarded as SU Ursae Majoris stars with an exceptionally long interval between superoutbursts; no normal outbursts are observed between them. The mass transfer rate is considerably lower than in typical SU Ursae Majoris stars. Observations suggest that an excretion disk of matter is being ejected from the system.