Mount Yari is one of the 100 Famous Japanese Mountains. The 3,180-metre-high peak lies in the southern part of the Hida Mountains of Japan, on the border of Ōmachi and Matsumoto in Nagano Prefecture and Takayama in Gifu Prefecture. The priest Banryū founded a temple there. The headwater of Japan's longest river, the Shinano River, begins he…Mount Yari is one of the 100 Famous Japanese Mountains. The 3,180-metre-high peak lies in the southern part of the Hida Mountains of Japan, on the border of Ōmachi and Matsumoto in Nagano Prefecture and Takayama in Gifu Prefecture. The priest Banryū founded a temple there. The headwater of Japan's longest river, the Shinano River, begins here as the Azusa River.