to prevent trafficking in stamps during times of currency disruptions. As the Communists liberated various parts of the country they too overprinted available stamps including the Sun Yat-sen issues under regional authorities, and they did not begin issuing stamps for the entire country until they had consolidated power. Another large group of overprints occurred after the war when the Chinese National Currency was introduced. This currency devalued rapidly, as did the Gold Yuan which replaced it. This led to two series "revaluation" surcharges in the post-war era. These were done by a number of different printers in various cities resulting in a variety of styles, fonts, and colours in the overprints. A few overprints were used to create commemoratives; these include the 1941 issue for the 30th Anniversary of the Republic, and the 1943 North China Japanese occupation issues to commemorate the Return to China of Foreign Concessions. Commemorative Issues Sun Yat-sen has been highly revered by all political sides for having ended the old dynasty system of China. Commemoratives celebrating Sun were thus issued both before and after 1949, and by both the Republic of China and the People's Republic of China. The Republic before 1950 The first issue featuring Sun Yat-sen was the 1912-12-15 issue commemorating the revolution. There are twelve values in the set which was recess printed in Beijing perforated 14½. This set should not be confused with a very similar concurrent set depicting Yuan Shih-kai. The next issue to appear on 1929-05-30 marked the State Burial of Sun Yat-sen and depicts the memorial hall of his mausoleum. This structure which was commenced after Sun's death in 1925 is built on the side of a hill near Nanjing. The four stamps in this set were engraved and printed in Beijing, perforated 14. Overprints of this set were produced for use in Xinjiang, Yunnan and Manchuria. On 1944-12-25 a set of five stamps was released for the 50th Anniversary of the founding in Hawaii on 1894-11-11 of Xingzhonghui (興中會), or Revive China Society, predecessor of the Kuomintang (Chinese Nationalist Party). The stamp was lithographed with rubber plates by the Central Trust Bureau in Chongqing, and issued without gum. The following year on 1945-03-12 a set of six marked the 20th anniversary of Sun's death. This too was lithographed with a rubber plate at Chongqing, and issued without gum. In September 1946 a blue airmail stamp of $27