The rise in prices of electricity, gas, and other utilities due to high oil prices and import/export restrictions caused by the war in Ukraine, and the resulting increase in prices, are making headlines on a daily basis. For the past 30 years, the average salary income of Japanese citizens has remained the same, and many companies have implemented bonus and workforce reductions. The situation continues to be difficult for the people. What has been noticeable in this situation is that the public has become more conscious of the cost of living. For example, they switch to energy-efficient appliances to reduce utility costs and make it a habit to go to bed early and get up early to save on heating and cooling. Against this backdrop, Edo (now Tokyo), a city that utilized natural resources to build a recycling-oriented society, has been attracting attention. In the 18th century, Edo was one of the largest cities in the world with a population of one million and water and sewage systems were already in place. The ecosystem of that time was technologically superior, and there are many things we can learn from it even today. At the hear t of the Japanese people is a sense of value for things and nature that goes beyond mere frugality. The Edo period was supported by the MOTTAINAI spirit. Hal f a centur y ago, when we were plagued by pollution, we a chieved high growth that surprised the world by promoting energy-saving, resource-saving, and low-cost type technological innovations. Japan has always created new and improved ideas out of chaos. Crisis and opportunit y are two sides of the same coin. ( From May issue, 2023 / 2023年5月号より）