In this guide you’ll climb up from Sounkyo (層雲峡) to the summit of Mt. Kuro-dake (黒岳, Kuro-dake), then make the long traverse southwards to Mt. Kaun-dake (化雲岳, Kaun-dake), and finally descend to the hot spring town of Tenninkyo (天人峡). In this exhilarating and exhausting traverse, you’ll cross not only some of the most distinguished peaks in the Daisetsuzan, but the huge plateau of Takane-ga-hara (高根が原). It’s a long trek—3 days and 2 nights—but you can stay at the Hakuun-dake Lodge (白雲岳小屋, Hakuun-dake koya) and at the campsite at Hisago-numa Marsh (ヒサゴ沼, Hisago-numa). It's a great opportunity to see the best that Daisetsuzan has to offer at all times of day.
From Sounyko, you’ll take the ropeway and chairlift up to the start of the climb at the 7th station marker (七合目, nana-goume). The switchbacked trek to the summit of Mt. Kuro-dake is the journey’s biggest climb. Along the way, you’ll come across Yamazaki wolfsbane and Chinese yarrow; make sure to keep an eye on the flora as it changes with altitude. Past the summit of Mt. Kuro-dake and a little ways below sits the old Kuro-dake Ishimuro (黒岳石室), a stone mountain lodge where you can stay the night.
Past the lodge you’ll cross a little meadow called Utsukushi Fields (美ヶ原, Utsukushi-ga-hara), where its likely that you’ll see clusters of Aleutian avens, Peucedanum multivittatum, and wedgeleaf primrose, if you’re climbing at the height of summer. You’ll cross the Akaishi-gawa River (赤石川, Akaishi-gawa), which runs out of the huge Ohachi-daira (御鉢平) crater to the southwest. After the Akaishi, you’ll cross a the primrose-lined Hokkai-sawa Beck (北海沢, Hokkai-sawa) as you make your way upwards to the rocky Mt. Hokkai-dake (北海岳, Hokkai-dake). In the summer the whole mountain will be ringed with flowers.
From the summit of Mt. Hokkai-dake, you’ll have an incredible view of Ohachi-daira, but you’ll turn your back as you cross the flat Hokkai-daira Plateau (北海平, Hokkai-daira) towards the rock-strewn Mt. Hakuun-dake (白雲岳, Hakuun-dake) ahead. Here at the head of the Hana-no-sawa Beck (花ノ沢, Hana-no-sawa), you’ll probably find some snow in the gully until quite late in the season. You’ll reach Hakuun-dake junction (白雲岳分岐, Hakuun-dake bunki) at the top of a small pass; from the junction you’ll find trails heading across to Mt. Koizumi-dake (小泉岳, Koizumi-dake), Mt. Hakuun-dake, and the Hakuun-dake Lodge. From here you can make the trip up to the summit of Mt. Hakuun-dake if you feel up to it—the summit has terrific views of the back of Mt. Asahi-dake (旭岳, Asahi-dake) and the broad headwaters of the Chubetsu-gawa River (忠別川, Chubetsu-gawa).
From the junction you’ll head down to the hut via a narrow ravine—be careful along here as there might be some snow left over well into the summer. You’ll make your way down the flanks of Mt. Hakuun-dake and finally come to Hakuun-dake Lodge, which looks over tomorrow’s long journey: the huge Takane-ga-hara plateau. There’s a big campsite near the hut itself; behind the campsite is a huge rockfall where, if you’re quiet, you might hear the tiny squeaking of the pika. You can collect water from a stream near the campsite.
On day 2 you’ll cross Takane-ga-hara, summit Mt. Kaun-dake, and finish the day at Hisago-numa Marsh. From the hut, you’ll head down through a sea of dwarf stone pine to the plateau, the long trail before you sprawling out over the low humps. Before you set off, check for any signs of bad weather—the terrain ahead is rough and windblown and offers no shelter for kilometers. Along the way, look out for Ezo weaselsnout and Rishiri gentian flowering beside the trail.
By and by you’ll come to Takane-ga-hara junction (高根ヶ原分岐, Takane-ga-hara bunki), where a trail splits off to the east. This, the Mikasa New Trail (三笠新道, Mikasa shindou), is unfortunately currently closed due to trail erosion and bear activity. Continuing along the plateau, look for cairns here and there to guide you if visibility is poor.
Walking along the trail you’re sure to see komakusa bleeding-heart among the patches of dwarf stone pine ahead. You’ll cross the eastern flank of the round-topped Mt. Hira-ga-take on your way to Chubetsu-numa Pond (忠別沼, Chuubetsu-numa). The trail follows raised wooden platforms along the rim of the pond, where Kamchatka globeflower and woolly geranium grow.
From the asymmetric summit of Mt. Chubetsu-dake, you’ll have an amazing view of Mt. Kaun-dake ahead, especially over its vertical north face. Just south of Mt. Chubetsu-dake there’s a small hut and a campsite; if the weather is bad or if you’re not feeling up to the trek ahead, you can stay the night here and shorten today's hike a little bit.
From the Chubetsu-dake Hut junction (忠別岳小屋分岐, Chubetsu-dake koya bunki) you’ll start the climb up towards Mt. Goshiki-dake (五色岳, Goshiki-dake), heading through a dense tunnel of dwarf stone pine. At the summit of Mt. Goshiki-dake you’ll find a trail coming up from the Numa-no-hara Marsh in the east. The trail ahead continues through more dwarf stone pine; along here too it’s likely you’ll see some big piles of feces—you’re in bear country. Remember to pack out any trash you might produce in the mountains.
From the Kaun-daira Plateau (化雲平, Kaun-daira), you’ll have a wonderful view across a sea of green towards the three-peaked Mt. Tomuraushi-yama (トムラウシ山, Tomuraushi-yama). If the weather’s good, you can climb to the summit of Mt. Kaun-dake before heading to Hisago-numa Marsh. There will probably be some snow left on the slope above the marsh, so tread carefully.
You’ll start the day by retracting your steps back towards Mt. Kaun-dake. From the summit of Kaun-dake you can look back at the mountains you crossed to the north and dwell on the journey that took you here. It’s a long road out of the mountains towards Tenninkyo. Past the small Pon-numa Pond (ポン沼, Pon-numa) ahead, the trail is lined with komakusa bleeding-heart and mountain haregrass. Past here you’ll start the descent down a long, broad ridge. While the trail here isn't particularly steep, it's interminably long and there's little shelter from the sun. Ganbare.
At about 1360 meters above sea level, you’ll arrive at Garden No. 1 (第一公園, Dai-ichi koen), a small meadow where wedgeleaf primrose blooms in profusion. Over the Glehn’s spruce at the rim of the meadow, you’ll have terrific views towards Mt. Asahi-dake. Descend from the meadow and you’ll enter a quiet mixed forest of deciduous and evergreen trees. Keep an eye out for dragonflies as you wander along the south rim of the Tenninkyo gorge.
Once you’ve arrived at Takimi-dai (滝見台, lit. ‘waterfall overlook’), the hot springs of Tenninkyo will be shortly at hand—you have only to descend the steep Namida-zaka Hill (涙坂, Namida-zaka, lit. ‘hill of tears’) and you’ll be there.
In June will will remain enough snow in the mountains that you’ll want to bring a map and compass to follow the trail. From July through the end of August the flowers will be in full bloom. Along the ridgelines the first hints of fall will arrive as early as the end of August, with the first snows coming around the beginning of September. As it gets colder towards the end of September the snow will arrive for good.