Nagatoro in Saitama Prefecture. During Autumn, the rapids make for a tranquil setting. You can ride a boat down stream and catch a bus back to the starting point. Located at the far end of Saitama, a car is most convenient but public transport connects it all. Other sights ainclude the Hodoya Shrine and the Funadama festival, dedicated to the God of Water as a prayer for the safety of boatmen on water going downstream the Arakawa river is held on August 15th. Nagatoro is doable in a day but worth setting off from Tokyo early to get the best out of a day.