Japan’s flag consists of red circle and white background and the red circle in the center symbolizes. We call it “Hinomaru”. Hinomaru means rising sun in Japanese.
We usually stand to attention for national flag and pay homage to national flag like in entrance ceremony or graduate ceremony. National flag exist to show dignity of Japanese people.
We call only rice and a pickled plum inside “a hinomaru bento”. Because of its similality of image. As shown in the picture. In the Showa period, the hinomaru bento was a standard box lunch.
梅干し(umeboshi) is a Japanese pickled plum. It is very acidic and salty, so is very good accompany white rice. Although umeboshi is very acidic, but many people like.