
Since the Rausu-Onsen route is longer, in poor condition, and it is easy to get lost, it is only for experienced climbers. There are also very few climbers.
Walk along the mountain stream through the forest to about the midpoint of the route. The traverse along the way at Wall No. 1 and Wall No. 2 is in poor condition, so please watch your footing. From here, follow the painted guide marks along the stream and climb up to Tomariba. After Tomariba, some snow remains on a steep slope (Photo 1). The distance is short, but crampons are required because of the steep slope.

After that, following along the stream, you come to a large snow gorge below Byobu Rock (Photo 2). In normal years, the snow in this gorge completely melts in September. Crampons with at least 10 spikes are required, as some areas are quite steep during the climb.

Also, during the descent, if you go straight down on the snow, you’ll miss the turnoff to the right and end up at Sanshirui Pond. Please take sufficient care when going down! (Photo 3)
Photo 3: Turning point along the Byobu Rock trail. Here, the trail continues off to the right.
When you climb up a large snow gorge from Byobu Rock, you eventually get to a spot where the trail forks with one trail going toward Rausu-daira and the other trail toward Iwaishimizu. When there is remaining snow or mist, it is easy to lose your way along the trail, so be careful. After the snow melts, this area becomes a vast field of flowers. The area just below the summit is rocky, so be careful not to fall, and watch out for falling rocks. The entire length of the trail is bear habitat and encounters with bears are possible.