Why does Japan have such a flag?

The national flag of Japan is a white cloth with a large scarlet circle in the center, symbolizing the solar disk.
It has been used as an official symbol of the state since 1854, when Japan’s rapid exit from centuries of self-isolation began.

In Japan, along with Buddhism, the original ancient religion is widely spread – Shintoism, the cult of worship of the sun goddess Amaterasu. White color in Shintoism symbolizes purity, scarlet-the cleansing and life-giving energy of the sun.

Thus, the flag represents an unblemished and happy life in the land of the Rising Sun, as Japan is poetically called.