Tea is produced from processing the leaves and leaf buds of the tea bush, Camellia sinensis. China is the first country in the world to drink, produce and cultivate tea. It is thought that tea trees cultivated in other countries have their origin directly or indirectly from China. Some wild tea trees found in Yunnan Province are believed to be thousands of years old. The ancient Chinese long ago discovered the healing properties of tea leaves and used them as herbal medicines over many generations. For example, people added tea leaves to their food to supply nutrients or as an antidote to poison. It was not till the Han dynasty (BC 206-AD 220), that methods of preparing tea became more standardized and tea became a drink to rival that of wine. In the Tang Dynasty (AD 618-907), tea drinking was prevalent among noblemen and Buddhist monks. Zen masters regarded it as a useful drink because it not only increased their awareness but also the whole practice of tea-drinking was extended to the various aspects of life to enhance appreciation and awareness of one's existence in relationship to the environment, be it social or natural. The monks accumulated extensive knowledge of how to make use of tea-drinking to boost one's spiritual cultivation. Lu Yu, who had been an attendant to a Zen master, learnt how to brew tea and appreciate its qualities. He wrote the world's first tea monograph, The Classic of Tea (Cha Jing) around AD 760. This book advocates the benefits of tea drinking and systematically describes the cultivation of tea plants, the processing of its leaves, the skills needed for its preparation and its enjoyment as a daily beverage. An illustration of tea competition Since then, tea has evolved into a staple beverage in China. The general public drinks tea to cure a variety of ailments or simply enjoys it for its many unique flavors. Many intellectuals received inspiration from tea-drinking. They composed famous poems, wrote novels and essays, and created paintings after enjoying a good cup of tea. In time, a whole set of tea culture developed as a result. People found out that tea-drinking not only enhanced their health, but also, their emotions were soothed, elevated, and perceptions sharpened. They came to appreciate life much better. Artists and the literati found their creativity stimulated. Many thus become faithful followers of tea-drinking. The custom of drinking tea has then been turned into a big business, with huge commercial interests involved in tea distribution, tea wares manufacturing, and tea exports. Chinese tea arts spread to Japan in the sixth century, and it was introduced to Europe and America in the seventeenth and eighteenth centuries. Together with silk and porcelain, tea has been another important Chinese export to the world.