  Neutrinos and gravitational waves are the only direct probes of the inner
dynamics of a stellar core collapse. They are also the first signals to arrive
from a supernova and, if detected, establish the moment when the shock wave is
formed that unbinds the stellar envelope and later initiates the optical
display upon reaching the stellar surface with a burst of UV and X-ray photons,
the shock breakout (SBO). We discuss how neutrino observations can be used to
trigger searches to detect the elusive SBO event. Observation of the SBO would
provide several important constraints on progenitor structure and the
explosion, including the shock propagation time (the duration between the
neutrino burst and SBO), an observable that is important in distinguishing
progenitor types. Our estimates suggest that next generation neutrino detectors
could exploit the overdensity of nearby SNe to provide several such triggers
per decade, more than an order of magnitude improvement over the present.
