Nou Hakusan Shrine Grove

A Forest Where Two Climates Overlap

The wooded hill behind Nō Hakusan Shrine in Itoigawa stands out for one botanical reason. Trees that usually belong to colder, more mountainous parts of Japan grow on the same slope as trees that belong to the warm coastal south. Mongolian oak (mizunara), painted maple (itaya-kaede) and Japanese bigleaf magnolia (hōnoki) share the ground with broadleaf evergreens such as Japanese evergreen oak (akagashi), the bay laurel Machilus thunbergii (inugusu) and Neolitsea sericea (shirodamo). The Agency for Cultural Affairs found the mixture distinctive enough to designate the grove a National Natural Monument on 21 December 1937.

The hill is modest in scale. Known locally as Oyama, it rises only about 90 metres above the shrine buildings, a short distance inland from the Sea of Japan. Its size is part of the point. A compact slope holds a forest that, in strict ecological terms, should not all be here at once.

The Hill Called Oyama

Nō Hakusan Shrine sits at the foot of the grove, and the two have been bound together for centuries. The shrine enshrines Nunakawahime, a goddess linked across the Itoigawa region to the myths recorded in the Kojiki, alongside Izanagi and Ōnamuchi. Its main hall is a three-bay nagare-zukuri structure roofed in cypress-bark shingle, built in 1515. It carries the features of Muromachi-period carpentry and has been an Important Cultural Property since 1958.

Oyama is sometimes also called Miyama or Gongen-yama. Geologically it is a knob of volcanic breccia formed by undersea eruptions roughly a million years ago, the same rock that makes up nearby Benten-iwa. Behind the worship hall, spring water runs continuously from a carved dragon's mouth. It is counted among Niigata Prefecture's notable waters, and the April festival begins with ritual purification using it.

Because the hill belonged to the shrine, its forest was never cleared for timber or farmland. Centuries of that quiet protection are the reason an unusual woodland survived intact long enough to be studied and designated.

Why the Grove Was Designated

The 1937 designation was made under the natural-monument criterion that covers notable trees, ancient trees and shrine groves. What the surveyors recorded was not a single famous tree but a whole community of them behaving oddly for its latitude.

Broadleaf evergreen forest, the lustrous-leaved woodland that dominates much of southern Japan, thins out as it moves north along the Sea of Japan coast. Nō lies near the northern edge of where it can persist. On Oyama that southern forest type meets the deciduous, cool-temperate forest of the surrounding mountains, and the two interlace rather than replacing one another cleanly. A visitor standing on the path can see glossy evergreen leaves and the bare winter branches of deciduous trees within the same view.

Forests of this transitional character are uncommon, and most have been lost to logging or development. The Nō grove was recognised as a place where the boundary between two of Japan's major forest zones can still be observed in a small, accessible space.

Walking Through the Seasons

The grove reads differently month by month. In winter the deciduous oaks and maples stand bare while the evergreen oak and camellia hold their dark, polished foliage, so the canopy looks half-asleep and half-awake at once. Camellia (tsubaki) flowers through the cold months and into early spring. By summer the slope lies under deep shade.

Oyama is also known for sound. The hill marks the northern limit of the breeding range of the cicada hime-haruzemi (Euterpnosia chibensis), whose massed song fills the forest in the second half of July. The chorus was selected in 1996 for the Ministry of the Environment's list of one hundred soundscapes of Japan. The cicada's breeding ground here carries its own separate National Natural Monument designation, made in 1942.

Paths climb the hill from beside the shrine. The footing is uneven in places, and the volcanic rock turns slick after rain, so sturdy shoes help. The reward is a close look at a forest that botanists once travelled here to document.

The Shrine and Its Surroundings

A visit to the grove pairs naturally with the shrine below it. The treasure hall holds a wooden standing Shō Kannon statue, an Important Cultural Property carved from a single block of cherry wood in the late Heian period, together with votive ship plaques that belong to a designated folk-culture collection tied to the area's maritime worship.

The shrine's spring festival falls on 24 April each year. Its centrepiece is a sequence of bugaku court dances, designated an Important Intangible Folk Cultural Property in 1980 and said to have been transmitted from Shitennō-ji temple in Osaka. The final dance, performed against the setting sun, is the one local people wait for.

The coast nearby adds more to a day here. Benten-iwa, a craggy islet crowned by a small shrine, rises just offshore and can be reached on foot. Marine Dream Nō, a roadside complex by the harbour, is known for crab. Inland, Sakeguchi Onsen offers hot springs at the western foot of Mount Myōkō.