They are obsessed with them. Many people carry one at all times. And statistically, evey Japanese person owns 7 umbrellas, and as a nation they go through 100 million a year.
At the first sign of precipitation, and often before, they go up. There is no concept that a few drops of rain, 'spitting' as we say, is not going to hurt somebody. Rain, even in the Summer, which I find pleasant, is an evil in Japan, to be resisted and opposed like a foreign invasion or threat to civilization.
In fact, the sea of umbrellas in a crowd of Japanese is a symbol, I fear, of something more than just a few drops of water. It is, like so many things in Japan, symptomatic of a deeper malaise: the fear of nature in general. The same fear, the need and desire for nature to be feared, controlled and avoided, is behind the concreting of Japanese rivers, the chopping down of the forests, the concreting of the seashores, the fear of dirt and infection, even the traditional, thousand-year-old tradition of bonsai, where the natural power of a tree's growth is tamed and perverted. It is one of the great ironies of Japan- and there are many. For a country that is supposedly so enamoured of nature, exactly the opposite is reflected in the behaviour of the people.
Personally I despise umbrellas. One of my pet hates. They are unwieldy, clumsy, a waste of money, and often ineffective.
And if one is able to accept a certain level of precipitation, enough, say, to dampen the shoulders, umbrellas are unnecessary. Admittedly, at times rain is heavy enough to make going outside unpleasant, but if one waits 5 minutes the situation will almost invariably improve. This is because the level of precipiation is changing constantly, and statistically speaking, a random change is likely to trend towards the mean, in this case a situation of no precipitation. That is why a change in the rain, if the rainfall right now is heavy, is likely to be towards a state of rainfall that is less heavy, and very likely to be comfortable to a human being who is not childishly and unnaturally afraid of nearly the most benevolent of weather conditions.
And that's why I don't use umbrellas.
SPARTANS never use umbrellas.