The Maruyama River flows south to north through Toyooka and empties into the Sea of Japan . Its course is relatively straight between the middle reaches and the estuary. Various wild birds gather among the reeds and groves along the banks of the rivers, and many anglers come from various places for the sweetfish fishing season which opens in June.

In ancient times, an outflow of lava from the Kannabe volcano made the Jugo falls, the Nidan falls, the Hattan falls, and the lava beds were designated a national monument by Hyogo Prefecture.

Ase valley has 48 waterfalls along the upper stream of the Ase River . We recommend hiking and viewing the beautiful mountain stream amid the spring green or red leaves of autumn. There are auto campgrounds, and places to eat yamame (a kind of trout ), and Tono-san soba (buckwheat noodle) in the neighbourhood.

The area of these falls was chosen as one of the therapeutic forest walks in the Hyogo top 50 selection. The beautiful scene, which looks like white threads flowing, revitalizes people's mind and spirit .