  We report the discovery of several optical burst-like events from the
low-mass X-ray binary MS1603.6+2600 (UW CrB). The events last for a few tens of
seconds, exhibit a very fast rise and slow decay, and involve optical
brightening of a factor of 2-3. The flares appear distinct from the lower level
flickering and instead strongly resemble reprocessed type-I X-ray bursts as
seen in a number of other neutron star low-mass X-ray binaries. In conjunction
with the previously reported candidate X-ray burst, these confirm that the
compact object in UW CrB is a neutron star. We examine the optical burst
brightness and recurrence times and discuss how the nature of the system can be
constrained. We conclude that the source is most likely an accretion disk
corona source at an intermediate distance, rather than a nearby quiescent
system or very distant dipper.
