Mount Fuji & Hakone富士山・箱根

Fuji stands where three tectonic plates meet: the Eurasian (or Amur) plate, the Okhotsk (North American) plate and the Philippine Sea plate, which is pushing north and carrying the Izu peninsula into Honshu. The mountain you see is the youngest of several stacked volcanoes. Geologists name an older base, Komitake, then Ko-Fuji, the Old Fuji of roughly 100,000 years ago, and finally Shin-Fuji, the Young Fuji, which has built the near-perfect cone over the last 10,000 years or so.

Written records describe more than a dozen eruptions. The Jōgan eruption of 864–866 poured lava from a fissure on the north-west flank into a large lake called Senoumi and split it in two: today's Lake Sai and Lake Shōji are its remnants, and the lava field became the forest of Aokigahara. The lava tubes and ice caves around Narusawa and Fugaku are from the same flows.

The last eruption, the Hōei eruption, began in December 1707, 49 days after one of the largest earthquakes in Japanese history. It came not from the summit but from a new vent on the south-east flank, the Hōei crater, which is still visible from the Gotemba side. Ash fell on Edo, about 100 km away, for days, and the sand buried farms in the Sakawa river valley so deeply that flooding followed for decades.

Fuji is classified as active and watched around the clock by the Japan Meteorological Agency. A hazard map revised in 2021 widened the zones that lava could reach, and national planning now includes how the Tokyo region would cope with heavy ashfall. Hakone's Ōwakudani, a vent zone of the older Hakone volcano, showed small eruptions in 2015, and access there still follows the alert level.

Volcanoes that erupt are dangerous, and early worship of Fuji aimed to calm it. Asama or Sengen shrines were founded around the mountain to honour its deity, later identified with Konohanasakuya-hime, the goddess of blossoming trees. The head shrine, Fujisan Hongū Sengen Taisha in Fujinomiya, claims the summit itself as its precinct; its inner shrine stands at the crater rim.

From the medieval period, mountain ascetics climbed Fuji as a religious practice, mixing Buddhist and Shinto ideas. In the 16th and 17th centuries a wandering ascetic named Hasegawa Kakugyō is said to have practised in the Hitoana cave on the western slopes, and his followers formed Fuji-kō, confraternities of ordinary townspeople. In Edo, hundreds of these groups saved money to send members up the mountain in summer, dressed in white and chanting on the way.

Pilgrims usually started from Fujiyoshida on the north side, where lodges run by guides called oshi fed, housed and blessed them before the climb. The Kitaguchi Hongū Fuji Sengen shrine there marks the start of the Yoshida trail, and the route up from its cedar avenue is still walkable. For those who could not climb, Fuji-kō built fujizuka, small replica mountains of lava rock, in shrine grounds across Edo; a few survive in Tokyo.

Women were barred from climbing to the summit until 1872. In 2013 UNESCO listed Fuji as a cultural rather than a natural site, under the title of sacred place and source of artistic inspiration. The listing covers the upper mountain, the Sengen shrines, the oshi houses, the five lakes, springs such as Oshino Hakkai and the pine beach of Miho no Matsubara.

The Tōkaidō, the main road between Edo and Kyoto, crossed the Hakone pass, the hardest climb of the whole route. Travellers called it Hakone Hachiri, the eight ri (about 32 km) of Hakone, from Odawara up to the lake and down to Mishima. In 1619 the shogunate built a checkpoint, the Hakone Sekisho, on the shore of Lake Ashi to control movement between east and west.

Officials at the checkpoint looked hardest for two things: guns coming towards Edo and women leaving it. The wives and children of regional lords were kept in Edo as hostages under the alternate-attendance system, so a woman slipping out could signal rebellion. The checkpoint was abolished in 1869; the present buildings are a reconstruction completed in 2007 from records found in the 1980s, and the cedar avenue planted along the old road survives beside it.

Hot springs made Hakone a resort long before the railway. Yumoto, at the bottom of the valley, was a bathing stop for Tōkaidō travellers, and the seven springs of the valley were known as the Hakone seven baths. After 1868, foreign residents of Yokohama came for the cool air; the Fujiya Hotel in Miyanoshita opened in 1878 to receive them. The Hakone Tozan railway, finished to Gōra in 1919, climbs with three switchbacks and remains one of the steepest adhesion lines in Japan.

Fuji appears in Japan's oldest poetry anthology, the Man'yōshū of the 8th century, as a mountain too high for clouds to cross, and in later centuries it became the standard subject for painters of famous places. But the Fuji most people know comes from woodblock prints of the 1830s, when Edo travel boomed and publishers sold views of the road to people who had walked it or wished to.

Katsushika Hokusai's Thirty-six Views of Mount Fuji, published from about 1830, used the new imported Prussian blue pigment and showed the mountain from 46 viewpoints (the series was extended beyond its title). Two prints became world images: the Great Wave off Kanagawa, where Fuji is tiny behind the breaking wave, and Fine Wind, Clear Morning, the red Fuji. Hokusai followed it with One Hundred Views of Mount Fuji in picture-book form.

Utagawa Hiroshige's Fifty-three Stations of the Tōkaidō, published in 1833–34, turned the road itself into a series; Hakone is shown as a jagged mass of coloured rock above the lake with a procession crossing the pass. Late in life he made his own Thirty-six Views of Mount Fuji, issued in 1858. Both artists were collected in Europe in the late 19th century and influenced Monet, Van Gogh and Debussy.

The image keeps being reprinted. The old ¥5,000 and ¥1,000 notes carried Fuji reflected in Lake Motosu, taken from a photograph by Okada Kōyō, and the ¥1,000 note issued in 2024 has Hokusai's Great Wave on its back.