The Lower Reach Area extends from “Yakeyama” (the starting point for Oirase Sightseeing and the end of the Oirase Stream) to “Sobe” (an entrance to a bypass).In this area, tributaries like the Ose and Ohoronai Rivers, flowing from the left bank, and the Sobe River, coming from the right bank, make the stream wider. After heavy rains, the water can become turbid.The view is rather monotonous in terms of scenery with the exception of the beautiful “Shimeikei” area. One can see a majestic forest of beech and chestnut trees between “Sobe” and “Ose,” and this is a suitable place for observing ferns and mosses.
The middle reach area runs from “Sobe” to Kumoi Stream (Kumoi-no-nagare ), where you may enjoy numerous scenic mountain streams, including Asura Stream (Ashura-no-nagare ), Kumoi Fall (Kumoi-no-taki ), and so on. Most tourists tend to gather at these points. Please take precautionary measures while strolling on the nature trail along the stream, as the trail is parallel to a roadway at times. Please watch out for traffic during peak seasons. In the area from Samidare Stream (Samidare-no-nagare ) to “Ishiigedo,” and the upstream side of Shirogane Stream (Shirogane-no-nagare), the nature trail parts from the roadway and you may enjoy a quiet stroll. On the downstream terrace of Kumoi Stream (Kumoi-no-nagare ), a beautiful forest of beech can be seen.
From around Kumoi Stream (Kumoi-no-nagare ) to “Nenokuchi,” the beginning of the stream is the upper stream area. The cliffs come close from both sides to look more like a gorge. You may see from here that Oirase is a U-shaped valley. There is a huge group of trees several hundred years old, including beautiful Katsura trees (Cerciphyllum japonicum ) between an area of Shimai Fall (Shimai-no-taki ) and Kudan Fall ( Kudan-no-taki ). Katsura trees rooted in the deep valley create quite a solemn atmosphere. A calm stream lined with young Japanese beech (Fagus crenata ) trees follows Manryo Stream (Manryo-no-nagare ) to Nenokuchi.