천자
The title "Son of Heaven" i.e. 天子 (from 天 meaning sky/heaven/god and 子 meaning child) was first used in the Western Zhou dynasty (c. 1000 BC). It is mentioned in the Shijing book of songs, and reflected the Zhou belief that as Son of Heaven (and as its delegate) the Emperor of China was responsible for the well being of the whole world by the Mandate of Heaven. This title may also be translated as "son of God" given that the word "Tiān" in Chinese may either mean sky or god. The Emperor of Japan was also called the Son of Heaven (天子 "tenshi") starting in the early 7th century.