The documents showing how finances and messages were exchanged between overseas Chinese and their domestic relatives were stored and recommended for the UNESCO honor by the archives bureaus of Guangdong and Fujian provinces, from which the first batch of overseas Chinese originated.

The news means China now has nine pieces of documentary heritage listed on the Memory of the World Register, including "Compendium of Materia Medica," a classic of Chinese medication, and "The Yellow Emperor's Canon of Internal Medicine," China's earliest medical classic on record.

Worldwide, 299 pieces of documentary heritage from 100 countries have been listed on the register, the statement said.