The is an area in the southwest of Honshū, the main island of Japan. It consists of the northern part of the Chūgoku region, facing the Sea of Japan. Etymology The name San'in in the Japanese language is formed from two kanji characters. The first, , "mountain", and the second, represents the "yin" of yin and yang. The name means the northern, shady side of the mountains in contrast to the yang "southern, sunny" San'yō region to the south. History Early history The San'in region has numerous Paleolithic and Jōmon period (14,000 – 300 BC) remains, but its Yayoi period (300 BC – 250 AD) remains are the largest in Japan. The Mukibanda Yayoi remains in the low foothills of Mount Daisen in the cities of Daisen and Yonago, Tottori Prefecture are the largest in Japan. The site is still only partially excavated, but indicates that the San'in was a regional center of power in the period. The mythology of the Shinto religion is largely based in the Izumo area of the region, and the Izumo-taisha, or Izumo Grand Shrine in Izumo, Shimane Prefecture, is one of the most ancient and important Shinto shrines in Japan. The eastern part of Shimane Prefecture also had cultural and economic connections to the Asian mainland from an early period. San'indō The San'in region corresponds to , one of the gokishichidō, or five provinces and seven circuits established in the Asuka period (538–710) under the Ritsuryō legal system. San'indō refers not only to the ancient geographic region, but also the main road through the region that connected it to the capitol in Kyoto. The San'in encompassed the pre-Meiji provincial areas of Tanba, Tango, Tajima, Inaba, Hōki, Izumo, Iwami and Oki. San'indō route While the San'indō route was used for military logistics in numerous conflicts after the Asuka period, it more importantly served as a route for the transport of good to and from the region. The route reached its highest period of importance in the Edo period (1603–1867) when the Tokugawa shogunate formalized its route and shukuba post stations. The daimyō regional rulers used the San'indō for their sankin-kōtai mandatory journeys to Edo (modern Tokyo). Modern usage The San'in region now has no administrative authority. In modern Japanese usage it generally refers to the prefectures of Shimane, Tottori and northern area of Yamaguchi. The northern areas of Hyōgo and Kyōto prefectures are sometimes included