# Social Infrastructures To Date and Challenges Open for the Future

## Section 1 History of Social Infrastructures and Their Roles

## Development of Infrastructures Viewed in Chronological Order

The history of infrastructure development is long in Japan as well. Here is a retrospective review of the history of infrastructure development in Japan, starting from the ancient times (to the late Heian Period), through the medieval times (from the Kamakura Period to before the formation of the Edo Shogunate Government), to the modern times (Edo Period), modern age (from the Meiji Period to prewar years) and present age (from postwar years to the present time), along with discussions of how the infrastructures developed have been maintained and managed.

## (1) Ancient times - Budding infrastructures in Japan -

A documented account of infrastructures in the prehistoric days of Japan can be found in a Chinese book of history written in the third century, titled “Gishi-wajin-den.” An envoy from the Chinese country of Wei visiting Tsushima and the northern part of Kyushu in those days described the roads there as being no better than “animal trails” and remarked that he could not see people walking ahead of him because of gross vegetation. With the subsequent opening of the Tumulus Period, tumuli came to be built everywhere. Huge dimensions of these architectural structures attest to the advanced level of the civil-engineering technology in those days. According to Japan’s legendary history, the 16th generation Emperor Nintoku, the founder of the capital in Nanba, allegedly built Manda-no-tsusumi (Manda Levee) alongside Yodogawa River and a bridge across Ikaizu $ ^{Note 1} $ and opened a highway from the capital of Nanba to Tajihinomura $ ^{Note 2} $ .

In 645, a political reform known as “Taika Reform” began to accelerate the pace of formation of a nation of centralized governance based on “Ritsuryo” (system of code and ordinance), enforcing a system of complete state ownership of land and citizens and marking off local administrative districts. The Capitals of Fujiwara-kyo and Heijo-kyo, built in succession, were furnished with large networks of roadside ditch nets as drainage. In the river traffic-rich nation of Japan, there had been ports called “Tsu” or “Tomari” from the ancient times, but state-run ports called “Kunitsu” were newly developed from province to province from which to ship tributes to the government during the Ritsuryo period.

Road development was commenced from a military viewpoint for unifying warring provinces. The prototype of

roads had already been formed before Taika Reform (645), but roads entered a stage of full-scale development about during the reins of Emperor Tenchi and Tenmu (668-686), and seven trunk roads (Tokai-do, Tosan-do, Hokuriku-do, Sannin-do, Sanyo-do, Nankai-do and Saikai-do) were collectively called the “Seven Post Roads.”

Regarding the maintenance and management of infrastructures in those days, the Building and Repairs Statutes of the Yoro Code compiled in 718 dictated that ports, bridges and roads in each district be repaired from mid-September to October and that, whenever an important road was broken to deny passage, it be fixed at all times. The statutes proceeded