The Nagara River runs for 166 kilometers through the heart of Gifu Prefecture, in central Japan. Although some 830,000 people live along the river banks, the water is renowned throughout Japan for its pristine clarity. It is also famous for its abundant ayu ("sweetfish"), a species of freshwater fish that only live in unpolluted waterways, and which make a summer specialty for food lovers across the country.  John Moore was born in Ireland but has lived in Japan for 30 years. On this episode of Journeys in Japan, John explores the Nagara River, meeting with residents who feel a strong bond with this waterway and who work hard to keep the river clean and clear. Their efforts are maintaining the habitat of the ayu fish and supporting the work of local artisans.