The modern sun flag dates back to medieval times. It was flown as an emblem of early Japanese emperors and as a naval banner during the time of the 04 shogun 54.
The Japanese flag of today is known as the 04 hinomaru 54, or the Sun Disc flag. The sun disc visually expresses the name of the country--Japan--which means "Source of the Sun".
The need for a modern Japanese flag arose when the American Commodore Matthew C. Perry visited Japan in 1853. A treaty was signed that opened U.S. trade with Japan. Similar treaties were soon signed with European nations. With the new and expanding commerce opportunities, a flag was required to identify vessels navigating outside Japanese territorial waters.
The flag, in its present form, was suggested by Lord Nariakira Shimazu, head of the powerful Satsuma clan in southern Japan. He was successful in having it recognized as the Japanese flag on August 5, 1854.
In 1860, the Sun Disc was hoisted on the United States Navy cruiser Powhatten, which carried Japanese diplomats to Washington. The new Japanese flag was displayed for the first time to the rest of the world.
A special proclamation issued in 1870 established the form and size of the flag. The rectangular proportion is 10 units for the length and 7 units for the width. The diameter of the sun must be three-fifths of the width. Often the flag pole is bamboo, painted black every few inches and capped with a golden ball.
The sun disc flag was approved as the national flag on May 5, 1872. On September 5 of that year, the flag was flown for the first time in a national ceremony, when the emperor opened Japan's first railroad in Yokohama. Japan's Emblem The Chrysanthemum is the 04 mon 54, or heraldic symbol, of the emperor. A mon is similar to a coat of arms and is most often associated with a family rather than an individual.
Emperor Toba II, who ruled during the late 12th century, played an important role in the development of Japanese symbols. He chose the Chrysanthemum flower as his mon and had it engraved on items such as swords.
From 1192 to 1867, the 04 shogun 54 ruled Japan, and the paulownia flower replaced the Chrysanthemum as the mon associated with those in power.
When shogun rule ended in 1867, the emperor regained power in what is known as the Meiji Reform. The Reform marked the beginning of a new age. The emperor again adopted a flag bearing a Chrysanthemum as his mon.
