Mt. Rausu-dake (羅臼岳) is a rocky peak northeast of Shiretoko Pass (知床峠 Shiretoko-touge) and the tallest mountain in the Shiretoko Range (知床連峰, Shiretoko-renpou). From its base on either side—from Utoro (ウトロ/宇登呂) in the northwest, or Rausu Town (羅臼町, Rausu-chou) in the southeast—in all seasons it's an imposing presence. In olden times the Ainu called it chacha-nupuri, meaning 'old man mountain.' In fact, on the neighboring island of Kunashiri (国後島, Kunashiri-to, also called Kunashir in Russian), there's another mountain with the very same name.
The current name, Rausu, is said to come from Ainu ra-ush, meaning perhaps "river of the thing at a low place." What this signifies is unclear.
There are two trails up the mountain. The far more popular one starts on the northern side of the peninsula, at the hot spring called Iwaobetsu Onsen (岩尾別温泉). The less popular, and arguably more arduous hike, starts near Rausu Town on the south side of the peninsula. You'll find the trailhead at Rausu Campsite (羅臼キャンプ場, Rausu kyanpu-jou). This guide will introduce the climb up the Rausu Town side.
If you're interested in the climb up the Iwaobetsu Onsen side, we cover that trail in the Rausu-to-Io-zan traverse.
The trailhead sits at the far end of the Kuma-no-yu (熊の湯) hot spring, in Rausu Campsite. Almost immediately after setting off, you'll merge with the trail from Rausu Kanketsusen (羅臼間欠泉), a geyser closer to downtown Rausu Town.
After signing in at the hiking register, you'll pass Kogakure Falls (木隠れの滝 Kogakure-no-taki). Climb a little bit further on and you'll come to a spot colloquially known as Satomidai (里見台, lit. 'town-viewing overlook'). Around here you'll be in a very serene forest of oak and castor aralia. In fall, the Ezo bears, or higuma (ヒグマ), come here to feed, so feel free to make plenty of noise as you climb.
At about 500 meters above sea level, you'll come to a place called Haimatsu-bara (ハイマツ原, lit. 'field of dwarf stone pine'), where you'll enter a huge forest of, appropriately enough, dwarf stone pine. From here you'll be able to see the winding road of Shiretoko Pass off to your left. As you meander among rocky outcrops you'll pass Dai-ichi Kabe (第一壁) and Dai-ni Kabe (第二壁) (lit. 'No 1-' and 'No 2 Walls', referring, presumably, to the cliff faces). Past here you'll descend into the valley of the Tozan River (登山川, Tozan-gawa, lit. 'hiking river'), where the terrain will get a little rough.
You'll hike alongside the mineral-spring-fed stream for a little while; after the valley bends to the north you'll arrive at Tomari-ba (泊場, lit. 'place to stay overnight'). The ground here is the typical bare earth of a volcanic slope. Crossing the dried-up stream bed and passing into a forest you'll soon find yourself beneath a huge cliff called Byoubu-iwa (屏風岩, lit. 'folding-screen bluffs'). If there's snow around here, be careful on the descent, as many hikers descend too far and lose the trail as they pass the cliffs.
You'll climb a steep ravine alongside the cliffs of Byoubu-iwa and emerge on the slope below the summit to Rausu-dake. The trail winds off first north and then around west as you make your way to the big saddle of Rausu Plateau (羅臼平, Rausu-daira). Here, too, be careful not to lose the trail if there's still snow in the area.
If you're feeling bold, there's a small side trail bypassing the traverse and climbing directly to Iwashi-mizu (石清水), a small spring near the summit. It's probably not super hygienic, but it's tradition to drink at least a little from the dripping water here. It's been filtered through volcanic rock and sphagnum, so it's probably safer than drinking from, say, a river.
Watch your step as you climb up towards the saddle, as snow remains here in the gully well into the summer. At the top of the climb, you'll emerge onto the broad and thickly pined Rausu Plateau. You'll now be well and truly in the wilds of Shiretoko: broad, rocky, and densely packed with dwarf stone pine. It's not unheard of to camp here overnight—consider staying a little below the saddle, as it's a bit of a wind gap—and there's a food locker nearby, should you need it.
From Rausu-daira, you'll see the rocky summit a little ways off and above you. Passing through the fields of low pine, you'll soon arrive at the aforementioned Iwashi-mizu. Past here you'll climb hard, hand over foot, up a steep slope littered with huge lichen-covered boulders, before finally coming to the precipitous summit of Rausu-dake. The summit stands about halfway down the length of the peninsula itself, so the views from up here won't disappoint.
You'll head back down the same trail you came up.
Until about the end of July, there will still be a lot of snow in the valleys and ravines. From July to August the flowers will be at their peak, so look for pincushion plant, wedgeleaf primrose, and Kuril saxifrage along the trail. In late September the alpine bearberry will go bright red. In mid-September, the leaves on the trees will start changing. When the cold comes in and the first snows fall on the mountains, snow and ice will make the climbing quite hard from Rausu Plateau onwards.