The traverse from Mt. Asahi-dake (旭岳, Asahi-dake), the highest mountain in Hokkaido, across to Mt. Kuro-dake (黒岳, Kuro-dake) is among the most popular trails in the Daisetsuzan Range. The approach being fairly easy, the trail is popular with beginners and tourists. This has unfortunately lead to a good deal of overwear on the trail and poses a significant threat to the delicate alpine environment.
Because the trails will be packed in the summertime and even more so in autumn when the leaves are changing color, it’s best to avoid these times and hit the mountains when the crowds are thinner.
From Asahidake Spa (旭岳温泉, Asahidake Onsen) the ropeway will take you to Sugatami Station (姿見駅, Sugatami-eki) at 1600 meters, as if in one great bound. Here, past the treeline, the trail is almost totally exposed to the alpine wind. Once you pass the summit of Mt. Asahi-dake, you’ll want to judge the weather carefully to determine whether or not to proceed.
Heading along the trail from Sugatami Station, you’ll soon come to Asahidake Stone House (旭岳石室, Asahidake-ishimuro), alongside Sugatami Pond (姿見ノ池, Sugatami-ike). From here on out you’ll be climbing for a while along a lifeless rocky ridgeline. Along the upper part of this hike you’ll see Nise-Kinko-iwa Bluff (ニセ金庫岩, Nise-kinkou-iwa, lit. Fake Lockbox Cliff) off to the right — and the summit will be just ahead. The ostensibly real Kinko-iwa Bluff (金庫岩, Kinkou-iwa) will be off to the left of the trail, dropping down into Jigoku-tani Valley (地獄谷, Jigoku-tani, lit. The Valley of Hell). There are guidance ropes in the area, but be careful not to wander too close to the edge of Kinko-iwa Bluff.
From the *summit of Mt. Asahi-dake (旭岳山頂, *Asahidake-sanchou), you’ll get a 360-degree view of the Daisetsuzan: over Mt. Tomuraushi (トムラウシ山, Tomuraushi-yama) and the Tokachi Mountains (十勝連峰, Tokachi-renpou) to the south, and over to Ohachi-daira Crater (御鉢平, Ohachi-daira) in the east, around which the Daisetsuzan unfolds.
The descent along the northern slope of Mt. Asahi-dake is steep and quite long, potentially with some snow remaining in the vicinity (depending on what time of year you climb) — so be careful. At the col where the slope ends, you’ll run into Ura-Asahi Campsite (裏旭キャンプ場, Ura-Asahi-kyanpu-jou), where you can fill up on water. From here you’ll make a traverse to the east of Mt. Kuma-ga-take (熊ヶ岳, Kuma-ga-take) to Mt. Mamiya-dake (間宮岳, Mamiya-dake). This mountain was named after Mamiya Rinzo (間宮林蔵), a famous explorer of the late Edo Period.
From Mamiya-dake you’ll pass Naka-dake Junction (中岳分岐, Naka-dake-bunki) and Mt. Naka-dake (中岳, Naka-dake), arriving finally at Hokuchin-dake Junction (北鎮岳分岐, Hokuchin-dake-bunki). Through here the elevation changes relatively little, so it should make for a pleasant walk — unless the winds are strong.
Especially from June to September, the temperature can be comparatively low up here; and in summer you might encounter severe hail. But even in the parts of Hokkaido least hospitable to life, alpine plants can take root.
From Hokuchin-dake Junction to Mt. Hokuchin-dake (北鎮岳, Hokuchin-dake) takes about an hour in either direction. If you’ve got some extra time, it’s an easy hike up to some spectacular views of Mt. Aibetsu-dake (愛別岳, Aibetsu-dake).
Past the junction on the eastern slope, it’s likely that you'll encounter a good deal of snow remaining. Dominant winds across the mountain deposit huge amounts of snow here, so several meters' thickness will remain even into July. Along this descent you can fill up your water bottles from the runoff snowmelt in a little ravine off to the left.
Once you’ve come around the north side of Ohachi-daira Crater, you’ll follow the left bank of the Akaishi-gawa River (赤石川, Akaishi-gawa), which runs out of Ohachi-daira, and emerge onto Kumo-no-taira Plateau (熊ノ平, Kuma-no-taira). Along this volcanic plateau you’ll run into a number of flowers growing off the late spring’s snowmelt: Rhododendron aureum (キバナシャクナゲ), Phyllodoce aleutica (アオノツガザ クラ), Geum pentapetalum (チングルマ), and Primula cuneiforma (エゾコザクラ). These flowers are spread out like a carpet along the plateau. In fall, here, the foliage is especially beautiful.
You can stay the night at Kuro-dake Stone House (黒岳室, Kurodake-ishimuro) or at the adjoining campsite. From the summit of Mt. Kuro-dake (黒岳山頂, Kurodake-sanchou), you’ll be able to see over the Daisetsuzan and all the way back to Ohachi-daira Crater. It's agreed that the view from here, over the many wrinkles, gullies, and bluffs of the Daisetsuzan, is like something off a painted folding screen.
The steep slope off Mt. Kuro-dake is a road laced with tall alpine plants. At the ropeway station bottom of the slope you'll find the 7th station marker (七合目, nana-goume), as well as a chairlift which will take you down to the ropeway (cablecar) station. From here it's a quick jaunt back down the ropeway and off the mountain.
To get to Asahidake Spa, get off the train at JR Asahikawa Station (JR旭川駅, JR Asahikawa-eki) and take the Yugou Service (湯号, Yuugou) of the Asahikawa Kidou Bus (旭川軌道バス, Asahikawa-kidou-basu). You could alternately take a taxi, but that’d be pretty expensive.
You’ll want to head out early, since you have to catch the last ropeway at the end of the day. The schedule fluctuates with the season, so check the operating hours before heading out, here. (The link is in Japanese, but it uses western numbers so it should be pretty easy to sort out.)
At Asahidake Stone House and at Ura-Asahi Campsite there are booths for portable toilets. Check the particulars of their use with the Mt. Asahidake Visitors Center (旭岳ビジターセンター, Asahidake-bijitaa-sentaa).
If you head down the hill to the west of Naka-dake Junction (中岳分岐), you’ll run into the open-air Naka-dake Hot Spring (中岳温泉, Naka-dake-onsen). Boiling hot water bubbles up through sand here and the only temperature control is a nearby stream you can divert. From the trail here you can pass across Susoai-daira Plateau (裾合平, Susoai-daira) and return to Sugatami Station (姿見駅).
The Kurodake Stone House is open from June to September, with a permanently stationed manager. There is a fee to stay there and also a fee to use the toilet there. The lodge can accommodate about 100 people.
Even in summer, it’d be wise to bring along some kind of cold weather gear (coat, gloves, hat, &c.), since the weather can turn pretty quickly. In the autumn, such gear becomes a requisite.