Lakes · Kanagawa
Lake Ashi
芦ノ湖あしのこAshi-no-koThe volcanic lake of Hakone, with Fuji on the horizon
Lake Ashi (Ashi-no-ko) is the lake of the Hakone volcano in Kanagawa Prefecture, formed about 3,000 years ago when a volcanic collapse dammed a valley inside the caldera. Sightseeing boats cross it between the Hakone Shrine area and Tōgendai, with Mount Fuji visible on clear days.
Overview
Lake Ashi lies in the western part of the Hakone caldera, some 80 kilometres south-west of Tokyo. Long and narrow, it stretches about seven kilometres from Kojiri in the north to Moto-Hakone and Hakone-machi in the south. Its name means 'lake of reeds'.
The southern shore was for centuries a stop on the Tōkaidō highway between Edo and Kyoto. The Tokugawa shogunate placed a checkpoint here in 1619 to control travel, and the cedar-lined old road and the reconstructed Hakone Checkpoint still recall this role. The red torii of Hakone Shrine, standing in the water at Moto-Hakone, is the lake's best-known image.
Today the lake is the centre of the Hakone sightseeing circuit: ornate sightseeing ships cross it, connecting with the ropeway to Ōwakudani and the mountain railway down to Hakone-Yumoto. On clear days, mostly in the colder months, Mount Fuji appears over the western rim.
Landscape and formation
The Hakone volcano formed a large caldera in eruptions more than 60,000 years ago. Around 3,100 years ago a steam explosion and collapse of the central cone Kami-yama sent a debris avalanche into the valley of the Haya River, damming it and creating the lake. Submerged trees still standing on the lake bed date from this event.
Ōwakudani, the steaming crater area on Kami-yama's flank above the lake, shows that the volcano remains active; the Japan Meteorological Agency monitors it.
Highlights
Hakone Shrine and its lake torii
箱根神社Hakone JinjaForest shrine at Moto-Hakone whose 'Peace Torii' stands in the lake.
Hakone Checkpoint
箱根関所Hakone SekishoEdo-period checkpoint on the Tōkaidō, reconstructed on its original site at Hakone-machi.
Old Tōkaidō cedar avenue
旧街道杉並木Kyū-kaidō SuginamikiAvenue of centuries-old cedars along the old highway between Moto-Hakone and the checkpoint.
Ōwakudani
大涌谷ŌwakudaniVolcanic valley of fumaroles above the north shore, reached by ropeway from Tōgendai; access depends on volcanic activity.
Kuzuryū Shrine
九頭龍神社Kuzuryū JinjaLakeside shrine to the nine-headed dragon deity of the lake, with a monthly lake offering ceremony.
Ecology
The lake was one of the first places in Japan where largemouth bass were introduced, in 1925; trout, smelt and other fish are also stocked for angling. Mixed forest covers the caldera walls, and the lake is surrounded by some of the best-preserved woodland in the Hakone area.
Flora
Hakone forest
Beech, oak and fir on the caldera walls, with bamboo grass and azaleas on the open ridges.
Fauna
Largemouth bass
ブラックバスburakku basuIntroduced from North America in 1925, the first introduction in Japan.
Rainbow and other trout
Stocked for angling from spring to winter.
Culture
According to tradition, the monk Mangan subdued a nine-headed dragon that terrorised the lake in the 8th century and founded Hakone Shrine, where the dragon became the protective deity Kuzuryū. The lake's water was also put to work early: the Hakone Canal, a tunnel through the western rim completed in 1670, still carries water to farmland in Shizuoka Prefecture.
Hakone Canal
箱根用水Hakone YōsuiIrrigation tunnel of about 1.3 km bored through the caldera rim in the 1660s, still in use.
History
c. 1100 BCE
A collapse of Kami-yama dams the Haya valley and creates the lake.
757
Hakone Shrine is established on the shore, according to shrine tradition.
1619
The shogunate sets up the Hakone Checkpoint on the Tōkaidō.
1670
The Hakone Canal through the western rim is completed.
1869
The checkpoint is abolished after the Meiji Restoration.
1936
Fuji-Hakone National Park is designated.
2007
The Hakone Checkpoint is reconstructed on its original site.
Through the seasons
Spring
Cherry blossom in April; azaleas and fresh green in May.
Summer
Cool relief from Tokyo; fireworks at lakeside festivals in summer, and frequent cloud.
Autumn
Colour on the rim from late October to mid-November.
Winter
The clearest views of Mount Fuji; the lake rarely freezes.
Routes and trails
Hakone round course
Circuit combining the mountain railway, cable car, ropeway via Ōwakudani, the lake boats and buses back to Hakone-Yumoto.
Old Tōkaidō trail
Stone-paved section of the old highway from Hakone-Yumoto up to Moto-Hakone and the checkpoint.
Lake Ashi west shore trail
Quiet forest path along the western shore between Hakone-machi and Kojiri.
Practical notes
- Hakone-Yumoto, the gateway, is reached from Tokyo (Shinjuku) by the Odakyū line or via Odawara on the Tōkaidō Shinkansen.
- Ōwakudani and the ropeway may be closed when volcanic activity increases; check the Hakone town site.
- Hakone is busy at weekends and in autumn; weekdays and early starts are quieter.
Frequently asked questions
Can you see Mount Fuji from Lake Ashi?
Yes, on clear days from the south and east shores and from the boats, but Fuji is often hidden by cloud, especially in summer.
How was Lake Ashi formed?
About 3,100 years ago a collapse of the Kami-yama cone inside the Hakone caldera dammed a valley, and the lake filled behind the debris.
What are the pirate ships on Lake Ashi?
Sightseeing boats styled as historic sailing ships that cross the lake between Tōgendai, Hakone-machi and Moto-Hakone as part of the Hakone circuit.
Where is the torii in the water?
At Hakone Shrine in Moto-Hakone on the south-east shore.
Related
Sources
- 1.富士箱根伊豆国立公園 (opens in a new tab) — 環境省
- 2.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
- 3.箱根町 (opens in a new tab) — 箱根町