Lying in the Isaryo region of Oguni Town, Hyakkoku-yama is a beautiful pyramid-shaped mountain when seen from Route 113. The story for Hyakkoku-yama's name goes that at some time in the past, there was as Steller’s sea eagle wreaking havoc on the locals. Some youngsters were able to eradicate the problem, and as a reward, the local lord gave them 100 (hyaku) Koku. From the lookout in front of the summit you can see the Yokokawa Dam and Ganko-yama. However, if you look further in the distance you can see as far away as the Ide Renpo.

Hyakkoku-yama Tozan Trail (90 minutes one-way)

Park your car at the former Isaryo Elementary School. Follow the narrow sealed road with the barrier and before long on your left there will be a sign for the trailhead. 10 m or so down you will see the next sign. This points you to the right up a slight incline through a cedar forest. Walking along the stream, cross where the two streams combine. Now starts the long incline.

After getting your fill at the Hyakkoku Shimizu spring, head towards the ridge. After 20 to 30 minutes heading north along a beech-covered ridge, you’ll emerge at a lookout. The summit is a few minutes walk to the right past the lookout. There is a summit marker and an open space, but unfortunately no lookout here.

Make sure you have snowshoes and other winter gear during winter hikes on Hyakkoku-yama. Plus, go with someone experienced in snow. On snow, there’s no need to strictly follow the trail. You can also use sleds or the like to get down fast and cut your hiking time considerably.