At 1333 meters, Mt Oobayashi (大林山) is the highest mountain overlooking Togura-Kamiyamada onsen on the west side of the Chikuma River valley. To get to the start of the climb, take route 77 south from Togura-Kamiyamada onsen. At the Mezawa Bridge intersection, turn right on route 55. After about 1 km you will see Chishiki Temple on the right. If you have time, stop and take a look around the temple, which has an 11-faced goddess that is displayed in public only once per year.
Follow the road as it winds up the mountain. Just before the tunnel, there is a car park on the left. The track starts from here and is signposted in Japanese (look for the wooden sign that says 八頭 大林 登り口). After about 200 meters the track reaches the old route 55. Turn right and follow the road for about 100m. The track then goes off to the left, up the hill. After climbing up the hill, you reach an intersection. The track on the right goes up a short steep climb to the top of Mt Hatto (八頭), although the views from here are somewhat obscured. We saw fresh bear droppings on the track here, so be careful.
Returning to the main track, turn right and follow the path to the summit. In the spring, you will see many purple and orange mountain azaleas flowering along the path. On a clear day, from the top you can see Mt Kamuriki (1252m) to the north. To the northeast is the Nagano City plain, and to the east, the Chikuma River valley at Togura-Kamiyamada.