Aso Milk Road (Daikanbo)

A dairy-pasture rim road along Aso's northern caldera wall, climbing to the Daikanbo overlook.

Nicknamed the Milk Road for its origins hauling milk down from the highland dairy farms, this is Kumamoto Prefectural Route 339 (with connecting stretches) running along the northern outer rim of the vast Aso caldera. From the Ozu and Otsu side it climbs through rolling green pasture before tracing the rim toward the Daikanbo overlook, where the Five Peaks of Aso, the caldera floor and the distant Kuju range open up in one sweep. The driving is flowing and grassy rather than technical, with long sight lines broken by the odd tighter rim bend, which makes it a favourite touring road and stargazing spot. It is open year-round but exposed up top. Mind free-roaming and crossing cattle, thick caldera mist that can drop visibility fast, and winter ice on the shaded rim sections.