Economic productivity, both agricultural and
industrial, rose steadily
during the early T'ang period. The introduction
of tea and wet rice from Annam
turned the Yangtse area into a vast irrigated
food bank and the economic base
for T'ang power. More food and rising population
brought increasing
manufactures. Chinese techniques in the newly
discovered craft of
paper-making, along with iron-casting, porcelain
production, and silk
processing, improved tremendously and spread
west through the Middle East.
Foreign trade and
influence increased significantly under the T'ang
emperors in a development that would continue
through the Sung era. Chinese
control in Central Asia reopened the old
overland silk route; but as
porcelains became the most profitable exports
and could not be easily
transported by caravan, they swelled the volume
of sea trade through southeast
Asia. Most of this trade left from southern
ports, particularly from Canton,
where more than 100,000 aliens - Hindus,
Persians, Arabs, and Malays - handled
the goods. Foreign merchants were equally
visible at Ch'ang-an, the T'ang
capital and eastern terminus of the silk
route.