Mt. Mashu is an 857-meter-high mountain located in Teshikaga-cho, Kushiro General Promotion Bureau, Hokkaido. It is the highest peak on the outer rim of Lake Mashu, a caldera lake, with a lake elevation of 502 m. Together with the mysterious Lake Mashu, it has been dedicated as Kamuinupuri "Mountain of God. The Ainu word Mashiu, of which there are various theories, means "a shadow appears to swim in the lake like a pot. Mt. Mashu is one of the volcanoes that make up Mashu Volcano and has a large crater, which was formed by volcanic activity after the Mashu caldera was formed. The latest activity was after about 4,000 years ago. From the first observatory, you can see the crater wall that has been cut vertically. The drop from the summit to the bottom of the crater (375 m above sea level) is 482 m. This hike is not so taugh. Everyone can try! The hightlight of this hike are beautiful morning sea of cloud and view from the trail seeing the cristal-clear Machu Lake.