Overprint on official stamps to reclassify them as regular postage stamps: "private" over the word "official", "0" over the "No." sign, a line obscuring the name and number of the district (school), and a new denomination of 1 kopek. Print run: 12 copies.
Official stamps were intended for official correspondence sent via the Zemstvo post. They were used in 1912β1914, issued free of charge but accounted for. Blue ones were for 10 medical districts.