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【JWF News Vol.165】Mission UCHIMIZU: Emotions are Differentials


【JWF News Vol. 165】Mission UCHIMIZU: Emotions are Differentials
July 18, 2018


◇ Contents ◇

・Foreword Mission UCHIMIZU: Emotions are Differentials


・Foreword Mission UCHIMIZU: Emotions are Differentials
By Kotaro Takemura, Chair of the Japan Water Forum


The season for UCHIMIZU has come around again. Since 2003, the Japan Water Forum has played a leading role in developing Mission UCHIMIZU across the country. The season begins on the day of Taisho, regarded as the hottest day of the year in the lunar calendar. Any individual or group is free to enjoy sprinkling water (UCHIMIZU) anywhere, anytime. There is only one rule: not to use tap water.

Participants are required to recycle secondary water such as used bathwater and dishwater. The aim is to encourage people to use precious water over and over again. The overall purpose of the JWF’s campaign is to help people re-discover the importance of water, experience this traditional Japanese custom and hand it over to the next generation.

Forgetting the importance of water as infrastructure develops
Even today in the 21st century, many people across the world suffer from a lack of clean drinking water. Many children are forced to spend several hours fetching water every day and are kept away from school.

In contrast, most Japanese people think we have an abundance of water. In fact, however, we often have brief, localized torrential rains. As the topography of Japan is very steep, rainwater quickly flows downstream into the sea. Most of the river water flows into the sea within a day. Even the water in one of the largest rivers in Japan, the Tone River, enters to the sea within a few days. Therefore, Japan suffered from serious droughts caused by dry spells since the old days.

Since the period of rapid economic growth after the World War II, Japan has made a great effort towards developing water infrastructure. We have constructed a good water system that captures in dams rainwater which would otherwise quickly flow into the sea, purifies it in water treatment facilities, and distributes it to each household.
Today, the Japanese can always access clean water simply by opening a faucet. With the development of water infrastructure, we have forgotten the importance of water.

UCHIMIZU events are aimed at making people become aware of the importance of water.

Emotions are Differentials
The effect of UCHIMIZU itself is limited. I don’t think we can conquer the heat island phenomenon and global environmental issues through UCHIMIZU. However, it has another impact.

When I took part in an UCHIMIZU event, I noticed one thing. The water I was scooping with my own hands from the pail felt very soft. When I water the plants on my balcony, the water spraying out of the hose feels very strong and hard. But water scooped with my hands felt incredibly soft.
The moment I sprinkled the soft water on the ground, it was felt as if the temperature around us had changed a little and a breeze was blowing through the area. When I scooped up the water with my own hands and felt a subtle change of air in my bones, I was rather moved, realizing that this was water.
Emotion is not simply a concept. We are deeply impressed the moment we see something change slightly, and experience it with our five senses.

In mathematics, the term “differential” refers to the amount that something physically moves within a short time. The wavering of something we feel with our five senses is a differential and this differential gives us strong emotions.
Feeling the differential caused by the soft water and subtle breeze while sprinkling the water, I thought about the destiny of infrastructure. By this I mean that people begin to lose interest in infrastructure when it is well-developed and properly supplied.

The Stock of Infrastructure is Integration
Seventy years ago, Japan was in ruins because of its defeat in the War. When reconstruction work began, people were delighted with the construction of houses and roads and were pleased when they saw water running from the taps in their houses and when electricity flowed into their homes.
The differential value of this infrastructure was very large. The larger the differential value of infrastructure was, the larger the joy of the population. People welcomed the construction of infrastructure almost unanimously. Since then, infrastructure has been developed and supplied in every area of Japanese society.

The nature of infrastructure is stock, not flow. Stock is regarded as integration in mathematics. The stock (integration) becomes larger every time a new infrastructure project is completed. As a result, the differential value of the effects of newly completed infrastructure becomes smaller and smaller. It is natural that people will no longer be impressed by the infrastructure with such a small differential value.

Though the stock of infrastructure is necessary, it is ironic that people will no longer be impressed by infrastructure and won’t understand it. While thinking about the destiny of infrastructure, I would like to feel a little excitement by taking part in UCHIMIZU events under the hot summer sun.




The old custom of sprinkling water with a ladle on streets and gardens, called “UCHIMIZU“, is a more well-known example of the use of water in Japan’s daily living.
People sprinkle water, especially in the summer time, in their house entrances and gardens or in front of their shops to lay the dust or to ease the heat.

In this example, people use water to feel its coolness.

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JWF News Vol. 165 / July 18 2018
Japan Water Forum

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