This chapter describes the proceedings of the conflict provoked by one of the worst environmental degradations of modern Japan. It emphasizes the various aspects of these historical events, and how the exploitation of the Ashio copper deposit in Tochigi Prefecture triggered an intense public debate on mining contamination at the turn of the century. Among other factors, scientific expertise mobilized both by protesters and the government contributed to the emergence of pollution as a social, political and environmental issue.

Introduction

On 18 December 1891, during the Diet of Japan's second session, Tanaka Shōzō (1841–1913), a representative from Tochigi Prefecture, called on the government to take action regarding the activities of the Ashio copper mine because they were contaminating agricultural land located downstream. Private property—protected by the imperial constitution—and the public good (kōeki) were at risk, he said. In the newly established Diet (1890), this intervention made a strong impression. While there had been local actions and denunciations prior to Tanaka's intervention, the fact that he raised the issue at the national level heralded the beginning of an intense social debate on industrial pollution.

Environmental degradation, however, was not something entirely new. Ancient and early modern Japanese societies had also put nature under pressure. For instance, on several occasions throughout history, forests were chopped down for major construction projects or to gain more agricultural land. In addition, the early modern period (1573–1867) saw contamination events due to mining activities, and records of complaints go back to the 17th century.

Nevertheless, in Japan, as elsewhere, from the end of the 19th century the expansion of industrialization damaged the environment at an unprecedented scale. Among other activities, mining, dyeing and chemical industries had a significant impact, affecting water, land, air and living organisms. In many places across the archipelago, toxic effluent and fumes harmed people's livelihood and health, sparking long-term disputes among actors representing conflicting interests.

The pollution from the Ashio mine is one of the worst environmental crises of modern times: at its peak in 1896, the river network had spread pollutants (arsenic, cadmium, lead and mercury, among others) to around 40,000 hectares of land downstream of the mine, across five prefectures and a part of Tokyo's territory.