Oshino Hakkai (the Eight Seas of Oshino)

Oshino Hakkai is a set of eight spring-fed ponds located in the village of Oshino in Yamanashi Prefecture, nestled between Lake Yamanaka and Lake Kawaguchi at the northern base of Mount Fuji. The ponds are fed by snowmelt from Mount Fuji that filters through underground lava layers for approximately 80 years before emerging as remarkably clear spring water. The name translates to "Eight Seas of Oshino," and these ponds have been recognized as part of the Mount Fuji World Heritage Site since 2013.

Historically, the area was once the bed of Lake Oshino, which dried up following volcanic eruptions around 800 AD. The eight ponds that remain have long been considered sacred, forming part of the Fuji-kō pilgrimage tradition where worshippers would purify themselves in these waters before ascending Mount Fuji. Each pond is associated with a Buddhist deity and varies in depth, with the deepest, Okama Pond, reaching 8 meters.

Visitors can walk freely around most of the ponds via well-maintained paths that wind through the traditional village setting. The water's extraordinary clarity allows views of the pond bottoms and swimming fish, while on clear days Mount Fuji provides a stunning backdrop for photography. The surrounding area retains its rural character with traditional thatched-roof farmhouses, watermills, and small shops selling local products including tofu made from the spring water. Several ponds have small shrines nearby, and visitors can sample the spring water at designated spots.

Oshino Hakkai is located approximately 100 kilometers west of Tokyo. The most convenient access is via the Fujikyu Railway Line from Otsuki Station to Fujisan Station, followed by a 15-minute bus ride on the Naikanko Line. Direct buses also operate from Shinjuku Station in Tokyo, taking around 2.5 hours. From popular Lake Kawaguchi, local buses reach the site in about 25 minutes. Entry to the pond area itself is free, though there is a small charge of around 300 yen to access one enclosed pond with an observation area and small museum.