* Astronomy

The national flag of Japan is a white rectangular flag with a large red disk (representing the sun) in the center. This flag is officially called Nisshki ("sun-mark flag") in Japanese, but is more commonly known as Hinomaru ("circle of the sun").
The Nisshki flag is designated as the national flag in Law Regarding the National Flag and National Anthem, which was promulgated and became effective on August 13, 1999. Although no earlier legislation had specified a national flag, the sun-disc flag had already become the de facto national flag of Japan. 
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