The national flag of Japan is a white flag with a large red disc (representing the rising sun) in the centre. The flag's official name in Japanese is Nisshoki ("sun flag"), but the flag is more commonly known as Hinomaru ("sun circle"). The Hinomaru was widely used on military banners in the Sengoku (Warring States) period of the 15th and 16th centuries. During the Meiji Restoration, the flag was officially adopted for use as the civil ensign by Proclamation No. 57 on February 27, 1870 (January 27, Meiji 3 in the Japanese calendar). However, the flag was not adopted nationally until August 13, 1999, by the Law Concerning the National Flag and Anthem.
Along with the national anthem Kimi ga Yo, the Hinomaru is considered a controversial symbol of the militaristic past of the country. Use of the Hinomaru was also severely restricted during the early years of the American occupation of the country after World War II, although restrictions were later relaxed. Japanese law did not designate any particular flag as the national flag from 1885 until 1999, although the Hinomaru was legally the national flag for the brief period from 1870 until 1885. Despite this, several military banners of Japan are based on the design of the Hinomaru, including the sun-rayed Naval Ensign. The Hinomaru was used as a template to design other Japanese flags for public and private use.