I'm not sure if this is relevant to the assighed topic, but the central red disk in the flag of Japan symbolizes the sun.
Here are some backgrounds. Britannica says that According to tradition, the sun goddess Amaterasu founded Japan in the 7th century bc and was an ancestor of the first of its emperors, Jimmu. Even today the emperor is known as the “Son of the Sun,” and a popular name for the country is “Land of the Rising Sun.”
