Following the outbreak of the Pacific War on December 8, 1941, the fall of Hongkong terminated stamp printing in that city. The new stamps were hence forth printed by the Central Trust of China, Chungking in typography. The design and decorations were almost the same as Dr. Sun Yat-sen stamps of the New York Print.
Owing to the shortage of materials during wartime, the art of plate making and stamp printing was not up to the required standard. The stamp paper was selected from local products, which were of 2 main classifications-native paper and woodfree printing paper. The native paper was not white and, though very smooth, the back was coarse. This was supplied by the Cental Paper Co. at Tungliang, Szechwan and was, therefore, called〝Tungliang paper〞(銅梁紙) or〝Central paper〞(中央紙) .Another kind of native paper without grain was the product of the Chung Yuan Paper Co. and was called Chung Yuan paper(中元紙). The woodfree printing paper was also classified as local woodfree printing paper and western woodfree printing paper. The former was the product of the Lung Chang Paper Co. and was called Lung Chang paper(龍章紙). It was coarse and loose, easy to be soiled or damaged, and usually left rough perforated teeth. The western woodfree printing paper was imported goods. It was tough and bright; stamps printed on such paper could be easily torn along the perforations.
10￠, 20￠, 30￠ $1 red, $1 green and $2 denominations were printed on both native papers and woodfree printing papers, while 16￠, 25￠, 40￠and 50￠denominations were only on native papers and $1.5, $3, $4 and $5 were only on woodfree printing papers.