Adopted in 1870; The flag of Japan white with a large red disk (representing the sun without rays) in the center. (ref: CIA World Factbook, Jan. 2014) The flag has been in use for many centuries. Known as the Hinomaru ("sun disk"), it is known to have been flown on ships since the early 17th century, and was formally designated as the national flag by the Meiji government in 1870.