It is thought that tea was originally grown in Yunnan Province. If you go to Yunnan , giant tea plants over 20 metres tall can still be seen here and there. The marvelous tea plant containing caffeine has undoubtedly been used by the people in this area since before the dawn of recorded history.
The use of tea leaves then moved northwards and the Han people came to know of it. (Succeeding the Ch'in Dynasty, the Han emperors completed the unification of China.) The first surviving written record of tea was made over 2000 years ago near Seito, the capital of Shisensho Province. It is a contract made with a slave and contains a passage ordering the slave to go and buy tea and to boil it. At the time the character , meaning 'tea', did not exist, so the character ,meaning 'bitter greens' was used.
Finally the culture of tea moved east along the Yangtze River and became established in what remains today the biggest tea growing area in China, Sekkosho. In the 5th and 6th centuries the culture of tea moved northwards and the dietary habits of the north could be broadly defined as being based on milk, with wheat being the staple food and meat the subsidiary food, whereas in the south tea was drunk, the staple food was rice and the subsidiary food fish.