"Leningrad Issue" — Imperforate stamps. Perforation (14.5 : 14.5) was carried out on official Goznak equipment without documentary authorization. Genuine examples are quite rare.
The third "Gold Standard" issue, February 1924 — March 1925.
Stamps of the first definitive series of the USSR, with denominations given in gold terms, went into circulation on 11 October 1923. Their issuance was connected with the transition to a gold-based currency. The stamp design is based on I. D. Shadr's sculpture "Worker" and matches that of the stamp of the fourth definitive issue of the RSFSR in 1923. However, the series also had distinguishing features. The word "post" was absent from the stamps. All stamps bore the new abbreviation "USSR". Denominations were indicated in the gold equivalent ("... kopeks in gold")—a hard currency that replaced the unstable ruble exchange rate, hence the philatelic name of this issue.