The Ota River, the mother of Hiroshima City, originates on Kanmuri
Mountain (1,339m), the second highest mountain in Hiroshima Prefecture. The
mountain, located southwest of Yoshiwa Village in Saeki-gun, is in the Quasi
National Park of the West Chugoku Mountains. The site is noted for its natural
beauty in all seasons. From the upper reaches of the Ota River in deep ravines,
abundant spring water runs its course through many tributaries into the main
flow of the river for 103 kilometers.
 The river boats, once vital for transportation, carried products and necessities
between the mountain districts and Hiroshima. Likewise, daily necessities like
bamboo for norihibi (used for laver culturing at Hiroshima Port) were sent back
by river transportation. Sometimes the river boats also became wedding boats,
taking brides from the hilly regions marrying into families down south beyond
Kabe. Thus, the Ota River was the main artery connecting the upper regions and
the city economically and socially. Around 1900, there were as many as 700 river
boats and more than 20 boat building houses along the river near Kabe. These
boats could be seen until the late 1920's.
 In the meantime, the hydroelectric power business was successful in the middle
and upper reaches of the river. The Kameyama Power Plant (2,100kw) was the
first official power plant utilizing the river's water. Its construction started in
October, 1910 and was finished two years later. The power plant, made of
dressed red brick, ceased operating in 1973, but the stately building still remains
at the site to this day.