The Chinese king Tang Xuan Zong of the Zang dynasty asked a monk who was more than 130 years old, "How could you live so long? Did you take any medicine for that?" The monk answered, "Drank tea daily, no thing else." Thus goes the legend.
China is the largest producer of Green tea, while Japan and Korea also contribute considerably. Green tea comes from the same plant as black tea, Camellia sinensis. What makes it different though is the manner in which the plant is processed. It is the least processed of the commercial teas. The leaves are picked and then immediately 'fired' -- a tea processing term, which means the leaves are either steamed or heated. The leaves are then dried. This process also helps retain the antioxidants that retard the aging process in human beings.