Emperor Saga
During 804AD, a Japanese Buddhist monk named Kukai Hoken Hyu travelled to the Tang Dynasty of China for two years. Upon return, he brought back books and calligraphy and began to propagate Buddhist teaching in Japanese society. Kukai had requested to present his discoveries to Emperor Saga. It was recorded that Emperor Saga was drinking chanoyu while reading through the books. As chanoyu means hot tea, this became the first record of tea drinking in Japan history.