What is flag in Japan?

the Japanese flag has the red circle, and that represents the sun. Japan litterely gets sunlight the fastest (interenational date line) so the circle means that Japan "meets" the sun the earliest.

they can't live without it

The current Japanese flag consists of a bright red disc on a white field. In this design, the red disc is representative of the sun, bringing to mind Japan's traditional nickname, "Land of the Rising...

A little red circle around pure white

White flag with red circle in the middle. It represents the rising sun.