8/05/2012 Japan, China
In 1937 the Japanese began their occupation of Northern China, and initially continued to use the existing stamps of China for postal purposes. By 1941 however, the currency in the unoccupied areas of the south of the country had depreciated. Subsequently, there was widespread smuggling of stamps into the north for re-sale at a profit.
In order to combat this speculation, the Japanese authorities ordered the printing of a series of controls onto the stamps; each of the six districts having its own two-character overprint with subsequent restricted usage. From 1942, as a counter-inflationary measure, it also became common for stamps to receive additional surcharges of half the original value.
These overprints have provided philatelists with an extensive range of issues for study.