Kumamoto · Mount AsoNo.509★★★Open in map →

Kusasenri Plain

— A grass-floored old crater below Mount Aso's active vent

natureThe classic — done right

A grass-floored old crater on the flank of Mount Aso, grazed by horses and cattle and ringed by the caldera's five central peaks. It stays open on the days when volcanic alerts close the crater above it.

FromAso Station
~30 minBus from Aso Station
Get off atKusasenri Aso Volcano Museum (Aso Kako Line bus)
From there
Kusasenri Plain

Directions ↗

Where it is

18 more notes in Kumamoto · open the map →

What to look for — in walking order

The Kusasenri terracethe viewing ground at the museum end, taking in the whole grass floor at once
Aso Volcano Museuma museum on the northern edge, showing a live camera feed from the crater rim
The grazing herdscattle and horses put out on the plain in the warm months, to be watched from a distance
The pond on the floora shallow rainwater pool in the middle of the old crater, its size shifting with the season
Mount Nakadakethe active vent across the plain, white with steam when the wind carries the plume this way

How to actually get there

Kumamoto Station → Aso Station (JR Hohi Line, changing at Higo-Ozu, about 85 minutes).
Aso Station → Kusasenri Aso Volcano Museum (Aso Kako Line bus, about 30 minutes).
Check the day's alert level at the museum, then walk out across the plain toward the pond.
If the crater is open, ride up from the mountain terminal; if not, keep to the plain and the low hills at its western end.

Aso Kako Line bus from Aso Station: JR Aso Station →(Aso Kako Line bus, about 30 minutes)→ Kusasenri Aso Volcano Museum, where the plain begins at the stop. Aso Station itself is reached from Kumamoto Station on the JR Hohi Line with a change at Higo-Ozu, roughly 85 minutes. Buses are not frequent, so note the return departure before walking out onto the grass.
Return from the museum stop: The same route runs back down to Aso Station from the stop in front of the museum. Services thin out through the afternoon and finish well before evening, so fix the return time first and let the rest of the day flex around it.

Directions from my location (Google Maps) ↗

About the place

Kusasenri is a grass floor of about 785,000 square metres lying in an old crater on the flank of Mount Aso. It sits inside one of the world's larger calderas, roughly 25 kilometres north to south and 18 kilometres east to west. Cattle and horses are turned out here through the warm months, and rainwater gathers into a shallow pond near the middle. Five peaks stand at the caldera's centre — Nekodake, Takadake, Nakadake, Eboshidake and Kishimadake — and Nakadake is the one still venting.

How to enjoy it

The toll road gate up to the crater opens at 8:30 for most of the year and at 9:00 in winter, closing in the late afternoon with the road shut overnight. Check the volcano council's page on the morning you travel, and check it again before leaving the museum. If the crater is open, go up first and keep the plain for afterwards.

Background & history

The plain is the floor of a shallow double crater on the mountain's flank, formed by a pumice eruption long before the present central cones took their shape. Grazing and controlled burning have kept it as open grass instead of letting it turn to scrub. A cable car once carried visitors from below to the crater rim, but repeated eruptions and earthquake damage put it out of service and it was withdrawn. A toll road and a shuttle bus do that job now, on the days the mountain allows it.

Before you go

Cash: The plain itself is free to walk on. The museum charges its own admission, the car park is paid, and the toll road up to the crater is charged separately on the days it opens.
Good to know: Everything above the plain is governed by Mount Aso's alert level. The level changes at short notice: when it rises, the area around the crater is closed (about one kilometre at level two, about two kilometres at level three) and crater visits stop. Kusasenri lies outside those zones. The toll road gate is shut overnight, and volcanic gas or weather can stop crater visits on any given day.
Another way: By car the plain is about 80 minutes from central Kumamoto and about 50 minutes from Kumamoto Airport on mountain roads. A direct bus also runs once each way per day between the city and the Aso mountain terminal.
After you get off: The bus sets down in front of the Aso Volcano Museum on the northern edge of the plain; cross the road and the grass floor starts a few minutes on foot below.