  We report the discovery of multiple condensations in the prestellar core
candidate SMM1A in the R~CrA cloud, which may represent the earliest phase of
core fragmentation observed thus far. The separation between the condensations
is between 1000 and 2100 AU, and their masses range from about 0.1 to 0.2
M_sun. We find that the three condensations have extremely low bolometric
luminosities (< 0.1 L_sun) and temperatures (< 20 K), indicating that these are
young sources that have yet to form protostars. We suggest that these sources
were formed through the fragmentation of an elongated prestellar core. Our
results, in concert with other observed protostellar binary systems with
separations in the scale of 1000 AU, support the scenario that prompt
fragmentation in the isothermal collapse phase is an efficient mechanism for
wide binary star formation, while the fragmentation in the subsequent adiabatic
phase may be an additional mechanism for close (< 100 AU) binary star
formation.
