Kosatsuba – Japan’s Medieval Billboards

After unifying Japan at the start of the 17th century, Tokugawa Ieyasu established five major highways, generally known as the Gokaidō (五街道), which connected the new capital of Edo (now, Tokyo), with the other major provinces of Japan. The most famous of these “Five Roads”–the coastal Tōkaidō and the mountainous Nakasendō–connected Edo with the former capital of Kyoto, and were often used by samurai to make their regular (read: mandatory) trips between the capital and their homes and castles in other places.

The many post towns along the Gokaidō served as rest stops and resupply points for travelers of all social classes, and since so many travelers passed through them, they were also excellent places for the Shogunate to post important news, new laws, and edicts, to ensure as many people as possible would see them. For that reason, the Tokugawa Shogunate built large kosatsuba, or “signboards” at the entrance and exit to each post town on the travel roads.

New laws and important edicts were written on wooden signs and posted on the kosatsuba for travelers and residents to read. The kosatsuba towered over the roadway–many were almost two stories tall–to ensure that even groups of travelers could see the shogun’s orders clearly.

Nakasendo Kosatsuba at the southern end of Narai-Juku, Nagano Prefecture

The photo above, which I took in the once-wealthy post town of Narai, near the midway point of the Nakasendo, shows both the typical position of the kosatsuba at the end of town and the way the village inns and restaurant/teahouses lined the travel road. Most portions of the gokaidō existed, and were used as travel roads, for centuries before Tokugawa Ieyasu unified them; for example, portions of what became the Nakasendo had been used to transport salt from the Sea of Japan to the cities in the Kiso Valley, and to take the sturdy little horses bred in the Kiso Valley to sell in other places around Japan.

Narai Kosatsuba

Large portions of the Nakasendo (and a couple of segments of the Tōkaidō) have been preserved and/or restored, and now exist as pieces of living history, so we can see the towns–and the news–as medieval travelers saw them.

Nakatsugawa Kosatsuba – Nakasendo – Gifu Prefecture

The signs are large and impressive. They’re often set above the road, on a hill or base, not only ensuring that passersby can see the shogun’s words, but giving the impression that the words are literally sent down from on high.

Although the boards are no longer in current use (the edicts posted on them now are reproductions), they’re fun to see, and an interesting piece of Japanese history.