イワオヌプリ いわおぬぷり Iwaonupuri
Kutchan and Rankoshi, Shiribeshi region, Hokkaidō
Ainu spellings: Iwaw-nupuri
Iwaonupuri cannot be seen from Iwanai harbour, but in the Edo period it was smoking and could not be ignored.
Location
42.8853, 140.6405 · Coordinates: OpenStreetMap Nominatim, 2026-09-10, on イワオヌプリ. Open in OpenStreetMap
Referents
- mountain Iwaonupuri (1116 m), the one active volcano of the Niseko range. The Edo-period maps and journals call it イワウ山, イオウ山 or 硫黄山, and Matsuura's 東西蝦夷山川地理取調図 writes ユワヲノホリ at the head of the Iwanai river system. The author argues that the Edo-period name Iwanai-dake covered the Niseko range as a whole.
Analyses
iwaw-nupuri
イワゥヌㇷ゚リ ‘sulphur mountain’ received readingProponent: zenibako_trek（小樽銭函地名歴史研究会） (zenibako_trek (Otaru Zenibako Place-Name and History Society))
The name reads as it stands. Identifying the mountain of the records with Iwaonupuri turns on three things: the smoke, which Iwanai-dake has never been recorded to give off; the distance, some 四里 or 15.7 km in the Bunka-era journals against about 15 km in a straight line from Iwanai harbour to Iwaonupuri and about 一里 to Iwanai-dake; and the pictures, where the sulphur mountain is drawn back and to the left of the big near peak. The hot spring on Iwanai-dake bears this out from the other side: Iwanai Maruyama is a sodium chloride spring with no hydrogen sulphide in it at all.
Evidence
- documents
Sulphur was worked here in three phases, from about 1800, from about 1850, and from 1870 to 1937. The Iō sandō, made in 1861 by Satō Nizaemon, carried the sulphur down to Iwanai, and a road of about five ri is said to have run there already in the Bunka years; the present prefectural road 66, the Niseko Panorama Line, follows it, and the footpath by the Ōyachi bog near Shinsennuma keeps the older, straighter line. A smelting works stood north of Iwaonupuri near the head of the Iō River, and traces of it remain. Alum came from the same mountain; the Goshiki hot spring at its foot is rich in sulphate, aluminium and potassium ions.
nupuri is a dictionary word in this sense, iwaw is Batchelor's Iwau, and the compound is ordinary; the mountain is an active volcano with worked sulphur on it, and no source contests the reading.
Attestations
- イワウ山 map Edo period 西蝦夷道中見取図
Drawn back and to the left of the largest peak, which is labelled ノツカ山 and is the present Iwanai-dake.
zenibako_trek… - イオウ山 map Edo period 北海道歴検図
Drawn separately from 岩内岳.
zenibako_trek… - 岩内硫黄山 map 1869 恵曽谷日記
Drawn from about the hill where the Tomari nuclear plant now stands, smoking clearly.
zenibako_trek… - 岩登山 map 1883 明治十六年札幌県治類典土地測量第一地理課
Attached to an application to work a sulphur mine. The drawn peak does not match Iwaonupuri itself but the neighbouring Ko-Iwaonupuri (1039 m), with the sulphur pit on its flank and smoke from the summit.
zenibako_trek…
Related names
- 小イワオヌプリ こいわおぬぷり — 1039 m, next to Iwaonupuri, with the sulphur pit on its flank. A track leads partway up and stops at the workings, which shows it was cut for the mining. The main peak shows bare white ground with little yellow sulphur visible, so Ko-Iwaonupuri may have erupted more recently. zenibako_trek…
- ワイスホルン わいすほるん — The peak the upper Horikappu tributaries actually rise on; its triangulation point is named 岩尾登. zenibako_trek…
- チセヌプリ ちせぬぷり — The only peak of the Niseko range besides the sulphur mountain whose name appears in Edo-period records. Niseko-Annupuri does not appear, and Nitonupuri was named by Hokkaidō University ski-club members after 二兎. zenibako_trek…