The victory of the plaintiffs in the Itai-itai disease trial was a major swell that prompted the Japanese government to improve pollution and sanitation. The "Basic Law on Pollution Control" had already been enacted in 1967, but in order to budget and make them into a policy, the"Environment Agency" (now the Ministry of the Environment) was established in 1972.
Then, February 28, 1973. The site of Japan's first pollution outbreak "Ashio Copper Mine" was closed. In addition, a settlement was reached between Furukawa Mining and the former victims. More than 80 years had passed since Shozo Tanaka complained to the Imperial Diet about the Ashio Copper Mine.
It is said that it was around this time that afforestation activities began in Ashio, which had become a bald mountain due to mining poisoning, an activity that continues to this day. The last of the four major pollution disease trials to be concluded was Minamata disease in Kumamoto.
Thus, sewage and fumes from factories and mines have gradually improved, and fish have returned to Tokyo Bay, which used to be a sea of sludge.
Since that time, there has been a movement to re-evaluate Shozo Tanaka as well, for example, his biography was adapted in textbooks of Japanese language, and documentaries on him as a clean politician were featured in TV programs on commercial broadcasters and public broadcasting stations.
The ultimate example is "Shozo Tanaka University," a citizens' organization founded in 1986 in Sano city, Tochigi Prefecture. The subject of these activities was not the stereotypical discussion of pollution as a shadow part of the economy, but a broader and deeper ideological debate.
Then, in 2013, an event was held to commemorate the 100th anniversary of Shozo Tanaka's death, in which the then Emperor Akihito (the current Senior Emperor Akihito) was invited to view "Shozo's Direct Appeal". In fact, it was not until May of following year that His Majesty Akihito visited the Sano City Folk Museum, where the direct appeal letters were kept. The fact that it was a private visit, and not an official visit, shew His Majesty's struggle between his responsibility as a symbol and his conscience.