
Provincial Map of Japan in the 8th Century CE
is a Japanese term denoting both an ancient division of the country, corresponding for the most part with the modern conception of the
San'in Region, and the main road running through it. ''San'in'' translates to "the shaded side of a mountain", while ''dō'', depending on the context, can mean either a road, or a
circuit, in the sense of delineating a region. This name derives from the idea that the northern side of the central mountain chain running through
Honshū was the "shaded" side, while the southern side was the "sunny" (山陽 ''
San'yō'') side.
The region was established as one of the ''
Gokishichidō'' (Five provinces and seven roads) during the
Asuka period (538-710), and consisted of the following eight
ancient provinces:
Tamba,
Tango,
Tajima,
Inaba,
Hōki,
Izumo,
Iwami and
Oki. However, this system gradually disappeared in the centuries leading up to the
Muromachi period (1333-1467).
The San'indō, however, continued to be important, and highly trafficked through the
Edo period (1603-1867). Running mostly east-west, its eastern terminus, along with those of most of the medieval highways (街道, ''
kaidō''), was at
Kyoto. From there it followed the coast of the
Sea of Japan to
Hagi, near
Shimonoseki, the western terminus of both the
San'yōdō and the San'indō, and very near the westernmost end of the island of Honshū. Though the road originally terminated in the west at
Hagi, the lords of
Chōshū Domain at some point during the Edo period changed it to end at
Yamaguchi.
As might be expected, the road served an important strategic and logistical role in a number of military situations over the course of the years.
Ashikaga Takauji in the 14th century,
Akechi Mitsuhide in the 16th century, and many others used it to flee from conflict, to return to the core of the country (''
kinai''), or to move troops. Many
daimyō also used this road as part of their mandatory journeys (''
sankin kotai'') to
Edo under the
Tokugawa shogunate. Of course, the road also served the more everyday purpose of providing transport for merchants, traveling entertainers, pilgrims and other commoners.
Today,
Route 9, the
San'in Expressway, and the
San'in Main Line of the
West Japan Railway Company follow the approximate route of the San'indō.
Reference
★ Sansom, George (1961). "A History of Japan: 1334-1615." Stanford, California: Stanford University Press.