It is notoriously true that much of thigh-grade opium imported for distribution in China today passes through Portuguese Macao. This opium comes from Iran, the principal external source of supply for the whole of Far East. […] Some months before Pearl Harbor, the Japanese succeeded in contracting for the bulk of Iran's raw opium export - the famous Red Lion Brand -in exchange for Japan's manufactured cotton and rubber goods (p. 121).
Source of Descriptive Information
Forman, H. (1948). Changing China. New York: Crown Publishers.