Aso City is located in the northeastern part of Kumamoto Prefecture and is home to Mount Aso, a famous active volcano. The area is designated as Aso-Kuju National Park, centered around the inner rim of the volcano. With numerous hot springs and leisure spots, the area is a popular tourist destination, attracting many riders for summer touring. Local specialties include ketchup made with fully ripe summer/autumn tomatoes, handmade natto made from soybeans grown with reduced pesticides on Mount Aso, and soba noodles made from buckwheat grown on the Namino Plateau. Aso is also one of the prefecture's leading hot spring areas, with roughly half of Kumamoto Prefecture's hot springs concentrated in Aso. The hot springs contain lithium, a rare element in Japan, making them popular for their stress-relieving properties.