National Parks · Kumamoto, Oita
Aso-Kujū National Park
阿蘇くじゅう国立公園あそくじゅうこくりつこうえんAso-Kujū Kokuritsu KōenA caldera you can live in, and grasslands renewed by fire
Aso-Kujū National Park spans the volcanic heart of Kyushu, from the huge Aso caldera and its active Nakadake crater to the Kujū volcanoes and Yufu-dake in Ōita. Designated as Aso National Park on 4 December 1934, it took its present name in 1986.
Overview
Aso-Kujū National Park covers the high volcanic plateau of central Kyushu. Its centre is the Aso caldera, a basin about 25 km from north to south and 18 km from east to west, surrounded by an outer rim and floored by towns, rice fields and railway lines where tens of thousands of people live. From the middle of the caldera rise the central cones of Aso, including the active crater of Nakadake. To the north-east, across the grassy uplands of Senomoto and the Yamanami Highway, stand the Kujū volcanoes, whose Nakadake (1,791 m) is the highest peak on the island of Kyushu, and further east Yufu-dake and Tsurumi-dake above Yufuin and Beppu.
The park was designated on 4 December 1934 as Aso National Park, and in 1986 renamed Aso-Kujū to reflect the importance of the Kujū area.
What makes the landscape unique is its grassland. Around 22,000 ha of pasture and meadow, among the largest in Japan, have been kept open for over a thousand years by spring burning, grazing and mowing. The practice sustains rare plants and insects and was recognised as a Globally Important Agricultural Heritage System in 2013.
Landscape and formation
The Aso caldera was created by four colossal eruptions between about 270,000 and 90,000 years ago. The last and largest, Aso-4, sent pyroclastic flows across much of Kyushu and as far as Yamaguchi Prefecture on Honshu, and scattered ash over most of Japan. After the collapse, new volcanoes grew inside the depression; these are the central cones, of which Takadake (1,592 m) is the highest and Nakadake remains one of Japan's most active volcanoes, with an acidic crater lake and frequent ash emissions.
The Kujū volcanoes are a cluster of lava domes and stratovolcanoes with fumaroles at Iōyama; a phreatic eruption in 1995 showed they are still alive. Between them lie high marshes, such as Tadewara and Bogatsuru, formed where water collects on impermeable volcanic deposits. Further east, Yufu-dake is a steep-sided lava dome with a twin summit.
Highlights
- 阿蘇山Aso-san
The central cones of Aso, where visitors can look into the steaming crater of Nakadake when gas levels permit.
Kusasenri-ga-hama
草千里ヶ浜Kusasenri-ga-hamaA grassy meadow in an old crater with a pond, grazing horses and a view of the smoking Nakadake.
Daikanbō
大観峰DaikanbōThe highest viewpoint on the northern outer rim, overlooking the caldera floor and the Five Peaks of Aso.
Komezuka
米塚KomezukaA small, perfectly shaped scoria cone on the grassy slopes of the central cones.
- くじゅう連山Kujū Renzan
A range of peaks around 1,700 m, including Nakadake (1,791 m), the highest on Kyushu island.
Tadewara and Bogatsuru
タデ原・坊ガツルTadewara, BogatsuruMountain marshes of the Kujū area, listed together as a Ramsar wetland in 2005.
- 由布岳Yufu-dake
A twin-summited lava dome (1,583 m) above the onsen town of Yufuin.
Nature
Ecology
The semi-natural grasslands of Aso and Kujū are the park's ecological treasure. Maintained by fire and grazing, they harbour plants that spread to Japan from the Asian continent during colder periods and survive here as relics, alongside grassland butterflies that have vanished elsewhere. The mountain marshes and scrub of Kujū add wetland species and some of Kyushu's finest displays of mountain azalea.
Flora
Higotai
ヒゴタイhigotaiA blue globe thistle, a continental relic of the Aso grasslands, flowering in late summer.
Miyama kirishima azalea
ミヤマキリシマmiyama kirishimaCarpets the Kujū peaks, especially Taisen-zan and Hiiji-dake, in pink in early summer.
Japanese pampas grass
ススキsusukiDominates the grasslands, turning silver in autumn.
Fauna
Shijimiaeoides divinus
オオルリシジミōruri shijimiAn endangered blue butterfly that depends on the burnt grasslands of Aso, its last stronghold in Kyushu.
Japanese Brown cattle
あか牛akaushiGrazed on the open pastures of Aso, part of the system that keeps the grassland open.
Sika deer
ニホンジカNihon jikaCommon in the forests and grasslands of the Kujū area.
Culture
Aso has been revered since antiquity. Aso Shrine, at the northern foot of the central cones, is dedicated to Takeiwatatsu, the legendary god who drained the caldera lake, and the Aso family served as its hereditary priests and later as local lords. The crater of Nakadake itself was worshipped as a deity.
The agricultural year shapes the scenery: in early spring the grasslands are burnt (noyaki), in summer cattle and horses graze, and in autumn grass is cut for fodder and thatch. On the Oita side, the park borders the hot-spring towns of Yufuin and Beppu, among the best known in Japan.
- 阿蘇神社Aso Jinja
One of Kyushu's oldest shrines; its tower gate was badly damaged in the 2016 Kumamoto earthquakes and has been restored.
Noyaki (spring burning)
野焼きnoyakiControlled burning of the grasslands, carried out by local communities with volunteers in early spring.
Hifuri Shinji
火振り神事Hifuri ShinjiA fire ritual of Aso Shrine in March, when burning bundles of grass are swung in circles at night.
- 由布院・別府Yufuin, Beppu
Hot-spring towns at the eastern edge of the park, below Yufu-dake and Tsurumi-dake.
History
c. 270,000–90,000 years ago
Four huge eruptions form the Aso caldera; the last, Aso-4, covers much of Kyushu.
1934
Aso National Park is designated on 4 December.
1986
The park is renamed Aso-Kujū National Park.
1995
A phreatic eruption occurs in the Kujū volcanoes.
2005
The Kujū marshes of Tadewara and Bogatsuru are listed as a Ramsar wetland.
2013
Aso's grassland agriculture is designated a Globally Important Agricultural Heritage System.
2014
Aso joins the Global Geoparks Network, later a UNESCO Global Geopark.
2016
The Kumamoto earthquakes cause landslides and damage across the caldera; Nakadake erupts in October.
Through the seasons
Spring
Black, freshly burnt grasslands turn vivid green by May; the burning itself takes place in March.
Summer
Miyama kirishima azaleas in June on Kujū; lush green pastures and grazing cattle; cool air on the uplands.
Autumn
Silver pampas grass waves across the caldera rim and the Senomoto plateau; maples colour the Kujū valleys.
Winter
Snow and rime ice on Kujū and the Aso rim; sea-of-clouds views from Daikanbō on cold mornings.
Routes and trails
Nakadake crater rim
A short walk from the upper car park to the crater edge, open only when volcanic activity and gas levels allow.
Takadake from Sensuikyō
A steep volcanic ridge climb to the highest of Aso's central cones, about three hours up.
Kujū from Makinoto Pass
The standard route across the plateau of Kutsukake and past the fumaroles of Iōyama to Kujū-san and Nakadake.
Yamanami Highway
A scenic road across the uplands from Aso via Senomoto and Chōjabaru to Yufuin.
Practical notes
- Aso is reached by JR Hōhi Line from Kumamoto in about one and a half hours; buses serve the central cones.
- Access to the Nakadake crater is restricted according to the volcanic alert level and volcanic gas; check the Japan Meteorological Agency and local announcements.
- Volcanic gas is dangerous for people with asthma or heart conditions, who are advised to stay away from the crater.
- Weather on the Kujū plateau changes quickly and fog is frequent; carry a map and warm clothing.
Frequently asked questions
How big is the Aso caldera?
About 25 km from north to south and 18 km from east to west, one of the largest calderas in the world, with towns and farmland inside it.
Can I look into the Nakadake crater?
When volcanic activity and gas levels permit, a viewing area on the rim is open; it closes whenever the alert level or gas concentrations rise.
What is the highest mountain in Kyushu?
On the island of Kyushu, it is Kujū Nakadake (1,791 m) in this park; Miyanoura-dake on Yakushima (1,936 m) is higher but lies on an outlying island.
Why are the grasslands burnt?
Spring burning (noyaki) stops forest from taking over and renews the pasture. The grassland it maintains is one of the largest in Japan and home to rare plants and butterflies.
Why was the park renamed in 1986?
To recognise the Kujū volcanoes and the Oita side of the park as equal in importance to Aso.
Related
Sources
- 1.環境省_阿蘇くじゅう国立公園 (opens in a new tab) — 環境省 (Ministry of the Environment)
- 2.環境省_国立公園_国立公園一覧 (opens in a new tab) — 環境省 (Ministry of the Environment)
- 3.全国の活火山 (opens in a new tab) — 気象庁 (Japan Meteorological Agency)
- 4.日本ジオパークネットワーク (opens in a new tab) — 日本ジオパークネットワーク (Japanese Geoparks Network)