Kusasenri is the soft counterpoint to Nakadake's fumes and warning signs: a wide grass plain with ponds, grazing horses, and the volcano rising behind it. It is easy to walk and easy to enjoy, especially if the crater road is closed.
The Aso Volcano Museum and visitor centre sit nearby, making this the practical hub of the upper mountain area. Even a short stroll gives a good sense of the caldera's scale.