Shinonsen is a town in San-in Region of Japan, the northern part of Chugoku Region.
San-in literally means the ying side of the mountains whereas San-yo is the yang side, the populated and heavily industrialized southern side and the gateway from Kyushu to Osaka. Hiroshima is in the San-yo region.
San-in, which is now very dispersedly populated and has almost no industry base, used to play a significant role in the ancient history of Japan. Izumo, which was located in now Shimane Prefecture was once a pivotal kingdom that gave birth to Japan as we know today, and is said to have constituted a pan-Sea-of-Japan cultural sphere along with the east coast of ancient Korea before conquered by Yamato people and has since never appeared again in the main stream of Japanese history.