This is a poster I happened to see in front of the station Kiosk.
It is advertising "perfect breakfast" that takes only a few minutes to eat.
(because people are very busy in Tokyo!!)
The character is eating a bowl of rice with Umeboshi, which we consider
as Japanese traditonal breakfast.
A bowl of white cooked rice with Umeboshi on top of it.
I think it is just a coincidence, but it looks like Japan's national flag, too.
Anyway, it is the most basic, most simple meal for us.
(of course we usually eat miso soup and grilled fish and so on for real breakfast though)

About Umeboshi, I read an interesting article recently.

It is referring to a book written by Boy George(of Culture Club) which is called "Karma Cookbook".
In that book, they say there is a recipe introduced as "Umeboshi Bancha Tea".
It is a very simple recipe - put half of Umeboshi (he tells what Umeboshi is later) and add
two table spoonful of soy sauce, and pour hot Bancha(a kind of Japanese tea).
Boy George writes as follows -
This drink is very good for a hang-over(tested on numerous occasions!).
What is even better is if you eat an umeboshi plum and suck the stone before your big night out.
Umeboshi is a Japanese plum, which when pickled has very strong taste.
It is an acquired taste - you either love it or can't stand it!