Aso

阿蘇市あそしAso-shi

Rice fields and grasslands within a giant volcano

Aso is a city in north-eastern Kumamoto Prefecture that occupies the northern part of the floor of the Aso caldera, one of the largest volcanic calderas in the world. It is the main base for visiting the active crater of Mount Aso, the grasslands of Kusasenri and the ancient Aso Shrine.

Overview

The city of Aso was formed in 2005 by merging the towns of Ichinomiya and Aso and the village of Namino. Most of it lies in the Asodani, the northern valley of the caldera, a flat basin of rice fields hemmed in by the steep walls of the outer rim, with the central cones of Mount Aso rising to the south. It is the name of both the volcano and the city, and should not be confused: the peaks, including the active Nakadake, are covered on their own page.

The caldera formed in four huge eruptions between about 270,000 and 90,000 years ago; the last of them spread ash across much of Kyushu. The surrounding grasslands, used for grazing and hay, have been maintained for centuries by spring burning (noyaki) and form one of Japan's largest expanses of semi-natural grassland. The area is part of Aso-Kujū National Park and the Aso UNESCO Global Geopark.

Aso Shrine in the Ichinomiya district, one of the oldest shrines in Kyushu, and the spring-fed shopping street in front of it are the historic core. Uchinomaki Onsen, in the centre of the valley, is the caldera's main hot-spring resort.

Landmarks

Nakadake crater
中岳火口Nakadake kakō
Active crater with a steaming, often turquoise lake; access depends on volcanic gas and the JMA alert level.
Aso Shrine
阿蘇神社Aso Jinja
Ancient shrine dedicated to the twelve Aso deities, with a large two-storey gate restored after the 2016 earthquakes.
Kusasenri
草千里ヶ浜Kusasenrigahama
Grassy crater basin with a pond where horses graze, below Eboshi-dake.
Komezuka
米塚Komezuka
Perfectly shaped small scoria cone, said in legend to be a heap of rice.
Daikanbō
大観峰Daikanbō
Highest viewpoint on the northern outer rim, overlooking the caldera and the reclining-Buddha outline of the central cones.
Aso Volcano Museum
阿蘇火山博物館Aso Kazan Hakubutsukan
Museum at Kusasenri explaining the volcano's formation and activity.

Districts

Ichinomiya
一の宮Ichinomiya
Shrine town with the Monzen-machi shopping street and its drinking-water springs.
Uchinomaki
内牧Uchinomaki
Hot-spring district in the middle of the valley.
Namino
波野Namino
Highland farming area on the eastern outer rim.

History

Aso Shrine was the chief shrine (ichinomiya) of Higo province, and its hereditary priests, the Aso clan, claimed descent from the deity Takeiwatatsu-no-mikoto, said to have opened the caldera to the rice farmers. In the medieval period the Aso clan became warlords controlling much of central Higo before being absorbed into the Katō and Hosokawa domains. The Hōhi road across the caldera linked Kumamoto with the Hosokawa's port on the Seto Inland Sea. Tourism grew with the opening of the railway in the early twentieth century and the national park in 1934. The 2016 earthquakes caused severe damage, including to Aso Shrine's great gate, which has since been restored.

c. 90,000 years ago
The Aso-4 eruption, the last of the caldera-forming eruptions, blankets much of Kyushu in ash.
Heian period
Aso Shrine is listed as the leading shrine of Higo province.
1918
The railway across the caldera reaches Miyaji, later completing the Hōhi Line.
1934
Aso National Park is designated, one of Japan's first.
1986
The park is renamed Aso-Kujū National Park.
2005
The city of Aso is formed by merger.
2014
Aso is designated a UNESCO Global Geopark.
2016
The Kumamoto earthquakes cut roads and rail links and topple the gate of Aso Shrine.

Culture

Life in the caldera is tied to the volcano and the grasslands: farmers burn the slopes in early spring, cattle and horses graze in summer, and the shrine's festivals follow the rice-growing year. The Aso Shrine rituals, including the fire-swinging rite and the rice-planting festival, are designated Important Intangible Folk Cultural Properties.

Festivals

Hifuri shinji
火振り神事hifuri shinji
In March participants whirl burning straw bundles at Aso Shrine to celebrate the marriage of a deity.
Onda Festival
御田祭Onda Matsuri
Summer rice-planting festival in which shrine maidens and women in white carry offerings in procession with the portable shrines.
Noyaki
野焼きnoyaki
Controlled burning of the grasslands in early spring, which turns the slopes black before new growth.

Food

Akaushi beef
あか牛akaushi
Lean beef from Japanese Brown cattle grazed on the Aso grasslands, often served as a rice bowl.
Takana meshi
高菜めしtakana meshi
Rice fried with pickled Aso takana mustard greens.
Aso dengaku
田楽dengaku
Tofu, taro, fish and vegetables on skewers, coated with miso and grilled over a hearth.

Getting around

The JR Hōhi Line crosses the caldera, with Aso Station about an hour from Kumamoto; limited express trains continue to Beppu and Oita.
Buses link Aso Station with Kusasenri and the crater area; a car is useful for the outer-rim viewpoints and Kurokawa Onsen.
Highway buses connect the caldera with Kumamoto, Aso Kumamoto Airport and Fukuoka.

Day trips

Kurokawa Onsen
黒川温泉Kurokawa Onsen
Riverside hot-spring village about 40 minutes north by road.
Kujū mountains
Volcanic highlands across the border in Oita, reached via the scenic Yamanami Highway.
Takachiho
Gorge and mythological shrines in Miyazaki, south-east across the mountains.
Minamiaso
南阿蘇Minamiaso
Southern valley of the caldera with the Shirakawa spring and small railway.
Kumamoto
The prefectural capital and its castle, an hour west.

Other cities in the prefecture

CapitalKumamotoKumamoto-shiA great castle, green avenues and spring-fed water CityAmakusaAmakusa-shiChurches, fishing harbours and the open East China Sea

Frequently asked questions

Is Aso a city or a mountain?

Both. Mount Aso is the volcano; Aso City is the municipality occupying the northern part of the caldera floor, from which the volcano is usually visited.

Is it safe to visit the Aso crater?

Access to the Nakadake crater rim is controlled according to volcanic gas levels and the JMA alert level and may be closed at short notice. People with asthma or heart conditions are advised not to approach the crater.

What is the best season for Aso?

Late spring and summer bring green grasslands, autumn silver pampas grass; in early spring the slopes are burned black.

How do I get to Aso from Kumamoto?

By JR Hōhi Line to Aso Station in about an hour, or by highway bus.

Sources

1.令和2年国勢調査 (opens in a new tab) — Statistics Bureau of Japan
2.阿蘇市ホームページ (opens in a new tab) — 阿蘇市
3.阿蘇くじゅう国立公園 (opens in a new tab) — 環境省
4.阿蘇ユネスコ世界ジオパーク (opens in a new tab) — 阿蘇ジオパーク推進協議会