Prior to the raising of the ordinary letter postage from 3￠ to 4￠ effective from November 1, 1922, a big quantity of 4￠ stamps were specially printed beforehand to meet the public requirements. With the reversion of the postage to the old rate from January 1, 1923, the 4￠ stamps were kept unused. As the 3￠ stamp stock gradually ran short, the 4￠ stamps were surcharged as 3￠.
The surcharge on Junk stamps invariably was made in No. 5 Sung characters and Arabic figures by the Printing Bureau of the Ministry of Finance, Peking by metal plates either in red or black characters.