His vision and action have advanced from researching “water transportation systems during the Middle Ages” to globally addressing “water for happiness, peace, and prosperity.” What are the thoughts of His Majesty the Emperor of Japan, who has served as honorary president of the United Nations Secretary-General’s Advisory Board on Water and Sanitation, on water? It was the first summer vacation period of the Reiwa era and the Emperor had navigated a busy schedule before attending to his research. Three months after his enthronement, he had restarted his study of water. I was invited to the Imperial Palace in order to present an academic lecture to the Emperor. And as usual, I was greeted with a gentle smile. The topics of discussion that day were varied: water supply, hygiene, climate change, water and food, energy, even culture and belief. It took well ... ... [Read more]