Information about legend: ХИЛЯДА И ТРИСТА ГОДИНИ БЪЛГАРИЯ

(from Bulgarian): One thousand and three hundred years [since the foundation of] Bulgaria.

In 1981 only, the regular legend on Bulgarian coins was changed from НАРОДНА РЕПУБЛИКА БЪЛГАРИЯ (Народна Република България - Narodna Republika Bulgaria, People's Republic of Bulgaria) to this one as part of the celebration of 1300 years since the country's foundation.