Hatchonoyu is known as the last remaining hidden hot spring in the Kanto region, located in the Okukinugawa Onsen area of Nikko National Park at an elevation of 1,300 meters along the upper reaches of the Kinugawa River. This historic single inn began as a mountain lodge in 1929 (Showa 4) and boasts over 95 years of tradition.

The name "Hatchonoyu" (Eight Cho Bath) originates from its location approximately eight cho (about 872 meters) from a woodworking workshop upstream where craftsmen made wooden ladles and magewappa (bent wood containers). Workers would stop by after their work, saying "Time for a bath," to soothe their fatigue, making it a beloved spot for the local community.

The greatest feature of Hatchonoyu is its 100% natural flowing hot spring water that emerges naturally from eight locations on the mountain slopes. Without any reheating, the freshly emerged spring water is directly channeled to each bath. The hot spring is considered a living entity that begins oxidizing the moment it emerges and touches air, gradually losing its efficacy. This allows visitors to enjoy the spring's full potency in its freshest state, earning it recognition as a heavenly blessed hidden hot spring.

The outdoor baths include "Yukiminoyu" (Snow-viewing Bath), the original open-air bath from the inn's opening in 1929, along with "Takiminoyu" (Waterfall-viewing Bath) and "Shakunagenoyu" (Rhododendron Bath) - three mixed-gender baths where guests can enjoy dynamic views of waterfalls. Takiminoyu offers a frontal view of the waterfall, while Shakunagenoyu provides a side view. There is also a women-only waterfall-viewing outdoor bath, and the mixed baths have designated women-only hours (21:00-22:00). Indoor baths were added in 1972 when materials could finally be transported by four-wheel-drive vehicles.

Accommodation consists of two types: the main building with its nostalgic retro atmosphere, and country-style log house cabins with warm wooden interiors. The log houses offer comfortable resort stays, while the main building serves as an ideal base for mountain climbing, fishing, and therapeutic bathing (toji).

Private vehicles are restricted beyond the Meotobuchiempty parking area, requiring either a 90-minute hike along the walking trail or use of the inn's shuttle bus service (available for overnight guests only). This inconvenience actually helps preserve the pristine natural environment, enhancing its value as "Kanto's last unexplored territory" and "Kanto's last hidden hot spring." As a member of the Japan Secret Hot Springs Association, it attracts visitors nationwide seeking an authentic hidden hot spring atmosphere.