One day in August I saw a photograph on page three of the English-language Japan Times newspaper showing women in a Tokyo neighborhood lined up on both sides of their local “shottengai” (shopping street) with pails, buckets and basins of water. They were dipping their hands in and splashing the water onto the road in a practice called “uchimizu.” First, you must understand that summer time in Japanis very hot, and this year summer was especially hot. Tokyosuffered a heat wave of more than 40-days of daily temperatures above thirty degrees Celsius. People cool off and try to cool off in a variety of ways, starting with air conditioners, swimming pools, trips to the beach, and wearing light summer kimonos (“yukata”)and traditional Japanese sandals like the “geta” (wooden clogs) or the “setta”(bamboo sandals). They also use “uchiwa”(fans with a handle) and “sensu”(folding fans), plus wind chimes (“fuurin”) are popular because their tinkling sounds make people feelcool. (That is the same reason why musical insects like crickets and cicadas are so popular in the hot summer. Their buzzing noise and chirruping make Japanese feel cool.)
It seems that what was going on was a symbolic address of the problem of the ‘heat island’ over Tokyo. The city pavement conserves heat making it feel hotter, longer - especially at street level - than it really is. The heat island is why, in my hometown, we sometimes saw toads and cats lying on city streets on summer nights. There might be some merit to the argument that cooling down the pavement by wetting it can have a measurable cooling effect - at least in the immediate surroundings.
Second, you must understand the agricultural origins of much of Japanese culture and the lingering rural affectations that persist even in modern urban life. Although Japan is characterized by large metropolises (and has been for centuries), large cities still look more like they are organized as conglomerations of small villages than as large, uniformly planned single units. The foci of every neighborhood in Japan are the small shopping streets where residents do most of their shopping and a lot of their socializing. (In addition, most residential streets throughout the country retain the narrow, meandering character of Middle Eastern Bronze Age villages. There are very few straight, broad avenues, and fewer roads and streets that have names. Consequently, an address in Japan is less a precise location like what we know in Canada, as it is a description of how to find a place. Accurate mail delivery sometimes depends on an individual postman’s familiarity with a neighborhood.) This custom of splashing water around the streets probably dates from a time before paved roads, when road traffic kicked up a lot of dust - especially in the hot, dry August weather. So I think that the habit might originate as a method of keeping down dust the same way that many rural gravel roads in Canada are still oiled in the summer time today - and maybe as a cooling mechanism as well, although I can’t imagine that it does (or ever did) make people measurably cool. Remember that in Japanhow things appear, how they look and feel is usually more important than how they actually are. So it is easy to understand how and why a custom that is said to make you feel cool in the hot weather can persist even if it has no such effect.
I have personally witnessed this water-splashing thing many times. I might be walking to the local train station in the morning on my way to work and I pass a flower shop, a toy shop or a futon shop just opening. One of the first things the shop master might do is to fill a basin of water and soak the sidewalk outside his business. Personally, I dislike it because it makes me feel dirty. It looks dirty, too. So I usually do my best to bypass or step around the shop, the shop master, and the wet sidewalk. I prefer not to walk through puddles, or walk through dirty mud or anything that looks unclean. I have always derived some private entertainment from the idea of how shocked Japanese would be if they realized what I was thinking, and saw the cultural chasm between us over even such a little thing. I think of it as the tip of a culturally tailored aesthetic iceberg.
I think there is more of ritual purity and cleansing about this custom than actual intention to clean. You know how when you walk into a Shinto shrine there is a fountain and water trough off to one side provided with ladles that people use to spoon out water, sip, spit and ritually clean their mouths? Well, keep that model in mind and when you think of the daily pavement washing that goes on in Tokyo and the rest of Japan. It is a kind of ritual ablution.