With summer fast approaching, the sweating hordes will no doubt flock to the air-conditioned paradises of shopping malls, cinemas and the frozen sections of their local supermarkets. But there is a more traditional and eco-friendly way to keep cool this summer, a technique that has been around since the Edo Period and is still widely practiced nationwide to this very day.
Uchi Mizu is the simple act of using a bamboo ladle and bucket to sprinkle water on the street outside your shop or house, usually while wearing a fetching yukata. It may seem primitive, but the water does not only cool the surface of the sidewalk (which is often paved with concrete, a serial offender for absorbing and storing heat), it also sucks cool air downwards as the water evaporates, much the same as our own natural defense against heat, sweating.
The evaporation may only cool the air by a couple of degrees, but the effects are clearly noticeable, not least because the air being drawn to street level can also alleviate the aggressive humidity that plagues the Kansai area every year.
Traditionally, the custom was just another example of how important community spirit is to Japan; as shop owners would not only wet the entrance to their own shop, but those next door as well. The water also helped keep the streets clean and so more inviting to potential customers. It may seem basic, but leaving food scraps on the floor on a scorching summer day does not only look dirty, it can cause a stench to frighten off even the most determined of shoppers.
Although it was once a common practice for shop owners, today, domestic Uchi Mizu has had a spike in popularity, as it is seen as a more environmentally friendly way to cool down the area surrounding your home. Some may think it is rather wasteful to pour perfectly good water on the floor, but the official English website (not perfect English, but English nonetheless www. uchimizu.jp/language/en), suggests that you either collect rainwater, or reuse bath water. They are also quick to point out that it can be beneficial to everyone, no matter their living arrangements: “It works not only on road surfaces, but also on roofs, verandahs, walls, both in sunny places and shade.”