Natural circulation ruble of Catherine.
On the reverse, initials of Yakov Chernyshev - St. Petersburg mincmaster from 1770-1776.
Obverse: bust of the Tsarina to the right, below her the mint mark СПБ, in the rim the legend:
Б-М-ЕКАТЕРИНА-II-IМП-IСАМОД-ВСЕРОС;
Reverse: eagle of the Russian Empire, on the sides of the tail initials Я-Ч, in the rim legend:
1773 МОНЕТА - РУБЛЬ;