SO 1920

Stamps with overprint SO 1920, which were valid for a limited period of time in the plebiscite territory of Eastern Silesia (Těšín). Several series were overprinted, e.g. Hradcany, express, newspaper and postage due stamps of independent Czechoslovakia. These stamps had a short life span and were for a limited territory, therefore the postage stamps used are usually of higher value than other common series of stamps of the Czechoslovakia I.