Iwaonupuri

 Image: Trailhead of Iwaonupuri (イワオヌプリ), Rankoshi Town - Summer 1977 

Iwaonupuri (イワオヌプリ) is a mountain located adjacent to Niseko Annupuri in Kutchan Town. The name originates from the Ainu language and is said to mean ''sulfur, mountain', according to the Hokkaido Government website (in Japanese), as sulfur used to be extracted from the mountain. The Japan Meteorological Agency's webpage lists its elevation as 1,116 metres, alongside 1,308 metres for Niseko Annupuri. The trailhead serves as an access point for both Iwaonupuri and Niseko Annupuri. 

Map: Trailhead for both Iwaonupuri and Niseko Annupuri

This place is also known for Goshiki Onsen (五色温泉: ごしきおんせん), a hot spring ryokan located within Niseko Onsenkyo (ニセコ温泉郷: ニセコおんせんきょう). According to the Summarised History of Niseko Town (in Japanese), an official webpage of Niseko Town, this Onsenkyo was designated as a 'National Health and Recreation Onsen Area' by the Minister of the Environment in 1958.

*'A National Health and Recreation Onsen Area' is a hot spring site designated by the Minister of the Environment under the Onsen Act, where the public use of hot springs is actively promoted, the health benefits of hot spring use are sufficiently expected, and the site is utilised as a wholesome recreational area. (Source: Ministry of the Environment)

So, you may wish to visit Goshiki Onsen after trekking both Iwaonupuri and Annupuri, in order to unwind and recover from physical fatigue.

This trailhead is located near an intersectional area betweent Kutchan, Niseko and Rankoshi Towns. Therefore, your location may vary depending on the specific point you are at. The summit of Iwaonupuri lies within Kutchan Town, the initial part of the trail is within Rankoshi Town and a parking area is located within Niseko Town.

Image: Trailhead of Iwaonupuri, Rankoshi Town - 1969

Image: Trailhead of Iwaonupuri, Rankoshi Town - August 1984

As shown in the images, this mountain has little vegetation due to its high sulfur content. In addition, the initial section of the trail is well maintained and even includes stone steps for visitors. So the site may be suitable not only for adolescents but also for young children.

Image: Hiking trail, Iwaonupuri, Rankoshi Town - Summer 1977

Image: Hiking trail, Iwaonupuri, Rankoshi Town - August 1984

Thanks to its location, between Annupuri and Iwaonupuri, you can also observe the distinctive form of Annupuri, which is internationally recognised for its ski resort. The images below were taken from nearly the same spot in 2009, 1977, and 1969 respectively. These show the enduring summer appearance of Annupuri, which may seem unfamiliar to you.

Image: Niseko Annupuri, Rankoshi Town - August 2009

Image: Niseko Annupuri - Summer 1977

Image: Niseko Annupuri - 1969

I was originally planning to hike both Iwaonupuri and Annupuri in the summer of 2025, during my return to Japan. However, due to scheduling difficulties on the part of a friend, who was going to accompany me, we eventually changed our plans and trekked Shioyamaruyama, instead. Hopefully, we will be able to visit this site the next time I return to Japan and if the plan is carried out, I will update this article with new photographs.

Image: Playing in a hot spring stream, Rankoshi Town - Summer 1977

For younger children, only the initial section of the trail is suitable for trekking. Even so, they often find ways to entertain themselves wherever they are. Therefore, visiting the site with your family may still be worthwhile.

Image: Iwaonupuri - 1969

Image: Iwaonupuri - Summer 1977

Image: Iwaonupuri - August 1984

There are no toilets along the hiking trail. Thus, the Goshiki Onsen Information Centre will be your final opportunity to use the facilities unless you are carrying a portable toilet on your way to the summit.

For your short journey, it is recommended to bring a bottle of water or tea, along with a change of clothes and a towel. Although it is said that the best season in Niseko is between summer and early autumn, due to low humidity and moderate temperatures, the weather in the mountains is unpredictable. Therefore, it is advisable to carry a map, compass, raincoat and similar essentials. Of course, be sure to wear appropriate trekking shoes.

Moreover, it is expected that you pass by other trekkers, so please enjoy the interaction with them along the way.

Iwaonupuri has a horseshoe-shaped crater at its summit. It is recommended to walk around the crater if conditions are clear and not foggy. 

Unfortunately, I do not have any photos of the summit at the moment, so please look out for updates next time.

Image: Iwaonupuri, Nieko Town - Summer 1977/ Car: ISUZU Gemini