This is a Russian Imperial 10 Kopecks blue definitive stamp featuring the double-headed eagle, overprinted in red with the word “RUB” (indicating revaluation). Issued during the turbulent Civil War and inflationary period of the early 1920s, these overprints were applied locally to revalue existing Imperial stock for postal use. Such issues are historically significant, as they reflect the breakdown of the centralized postal system and the widespread improvisations in different regions. Collectors value these stamps not only for their philatelic rarity but also for their strong connection to the revolutionary upheaval in Russia.