Tokushima Prefecture is located in the east of Shikoku, faces to Kii Channel to the east, and is adjacent to Kagawa Prefecture, Kochi Prefecture and Ehime Prefecture to the north, south and west respectively.Mountainous districts make up approximately 80% of Tokushima’s total land area of 4,146.65 km². Quite a few mountains in the districts exceed 1,000 m in height. The highest peak in Tokushima as well as the second highest in Shikoku is Mt. Tsurugi in the Shikoku Mountains with its altitude of 1,955 m. Tsurugi Mountains with Mt. Tsurugi at their center form a watershed dividing Tokushima Prefecture into north and south. The Yoshino River flowing along the north side of the Tsurugi Mountains rises from the distant Kochi Prefecture, flows into Tokushima Prefecture forming the steep Oboke and Koboke Gorges. The river then runs eastwards from Miyoshi City and flows wider, giving way to the wedge-shaped Tokushima Plains.The Sanuki Mountains with relatively low peaks are situated in the north of the Yoshino River. At the foot of the mountains, an alluvial fan spreads out, and the altitude of the land is high. Rice paddy area spreads in the lowlands downstream of the Yoshino River, same as the lowlands downstream of the Katsuura River and Naka River. There is a rich forest area in the southern slope of mountains in the watershed and not much wide flat ground.