Minamata Chronology

This chronology shows a history of the Minamata area regarding Minamata disease from the Meiji era to the present. Each item/event is given a reference to its source.

Abbreviations of reference sources

AC: Ayumi Chronology
The Editorial Committee of the Shin Nippon Chisso Labor Union’s photo collection (Jan. 2006).
The 59-year Footsteps of the Shin Nippon Chisso Labor Union We Created and Battled
KB: Kukaku Binran
Kumamoto Women’s College Research Institute of Regional Culture (1985). Shirakawa-ken ka Kukaku Binran (Handbook Zoning in Shirakawa-ken). Collection of History of Kumamoto prefecture No. 3
Kumanichi: Kumamoto Nichinichi Shimbun (Newspaper)
Kumamoto Nichinichi Shimbun Co., Ltd.
CH: City History
Minamata city (Oct. 1991). New History of Minamata City
SH: Short History
Takamine, Takeshi (March. 2008). Short History of Minamata Disease, Booklet of Minamata Disease No.6, Kumamoto Nichi Nichi Shimbun Newspaper
GS: General Survey
General Survey of Shin Nihon Chisso Hiryo Projects (July, 1937). The New Japan Nitrogenous Fertilizer Company (Nippon Chisso Hiryo K.K.)
CMD: Chronology of Minamata Disease
Arima, Sumio (Jan. 1979). Minamata Disease The 20-year Study and Assignment Today about Minamata Disease, Seirinsha
1874 Aug.-- The area of Minamata city later belongs to the 9th , the 10th, and the 11th subprefecture according to the revised the zoning system of administrative districts.
KB CH vol. 1 p. 498
1895 ---- Minamata-mura holds 2,543 homes, 379 trade/service industries, 222 industries, 27 eateries and 84 fisheries.
CH vol. 1 p. 648
1908 Aug. 20 Nippon Chisso Hiryo K.K. (hereinafter referred to as Nitchitsu) builds a factory of lime nitrogen (for the production of carbide) in Minamata-mura owing to the attraction of enterprise by Nagayoshi Maeda and others.
CH vol. 1 p. 649, GS p. 433
1909 Nov.-- The downtown Minamata-mura has electricity and the lights are turned on.
CH vol. 1 p. 649
1910 ---- The salt monopoly system started and the government promoted abolishing salt farms because of their low productivity. The salt industry in Minamata closed.
CH vol. 1 p. 649
1912 Dec.1 Minamata-mura adopts the administration system of town as a local public agency and is named Minamata-machi.
CH vol. 1 p. 650
1914 Dec.-- Nitchitsu newly builds a factory in Kagami-machi in Yatsushiro-gun. For the distribution of electricity to the factory, the Naidaijingawa Power Plant is built, but in 1926 it is taken over by a company called Dainipponjinpi.
GH p. 447
1915 Apr.-- Nitchitsu builds a new facility for Umedo port and starts the tunnel construction of Umedo. For its electricity supply, the Sendaigawa power plant is built in May, 1917.
CH vol. 1 p. 651, GH p. 452
1916 Apr.-- Nitchitsu starts infrastructure building for Umedo port and completed the following year. On September 14, its capital stock is increased to 10 million yen.
GS p. 452
1917 Apr.-- Minamata Jikka (practical course: the primary subjects related to the home and family) girls' high school is established. The higher course for elementary schools are set up at Kuzuwatari, Fukuro and Yude Elementary Schools. Telephone service starts in July.
CH vol. 1 p. 650
1922 May.-- Minamata Commerce and Industry Association is established. It holds 250 members among 1,030 trade industries.
CH vol. 2 p. 1233
1922 ---- Minamata-machi has 21,671people and 4,861 homes.
CH vol. 1 p. 650
1923 May.18 The three catastrophic floods before the 18th of June cause heavy damages. Seven houses in Yunotsuru and all the bridges except the Eidai Stone Bridge in Hama-machi are washed away.
CH vol. 1 p. 651
1926 Dec. 25 The Casale method is employed in the new facility of the Nitchitsu Minamata factory and starts manufacturing ammonia on Dec. 25th. The number of the factory employees is 1,665.
CH vol. 1 651, vol. 2 1235 GS464
1926 Jul. 21 The National railway of Hisatsu Coastline between Minamata and Komenotsu is opened.
CH vol. 1 p. 651
1927 May.2 Nitchitsu organizes Chosen Chisso Hiryo K.K. with 10 million yen in capital, and starts constructing the Hungnam Factory. On June 15, the headquarters office is located in Hungnam, Hamju-kun, Hamgyeongram-do in Hungnam in Korea. The site area is 32,675 acre.
GS p. 204, 474.
1931 Jan.15 Emperor Hirohito tours the Nitchitsu Minamata factory.
GS p. 530
1932 May.7 The Nitchitsu Minamata factory begins to operate a facility of acetaldehyde and synthetic acid as its first stage. The factory uses mercury sulfate as a catalytic agent and discharges the mercury.
CH vol. 2 p. 858
1932 Dec.-- Improvement work of Minamata-gawa River to change its course starts and is completed in April. The total construction cost is 538,336 yen. Also, the construction of the Hyakken port begins and completes in 1935. The total construction cost is 500,000 yen.
CH vol. 1 p. 653
1933 ---- Yunoko Road and a slaughter treatment site (the construction cost: 14,400 yen) are constructed. Water supply works (the cost: 335,000 yen) and an improvement work of Fukuro-Modo Road is done.
CH vol. 1 p. 655
1945 Mar.29 A campaign of US aerial raids on the Nitchitsu Minamata factory continued until August, not only completely destroying the factory is fully destroyed but also destroying 184 houses and killing or injuring some dozens of people.
CH vol. 1 p. 656
1945 Aug.15 Due to Japan's defeat in World War ll, Nitchitsu lost its overseas assets including assets in Korea. According to the Act for Elimination of Excessive Concentration of Economic Power, each domestic workplace of Nitchitsu is split off. Only the Minamata factory remains as a Nitchitsu factory.
CH vol. 2 p. 512
1946 Jan.26 The labor union of the Nitchitsu Minamata factory was established. Masao Noda became the union president among 3,214 members. Each union of Minamata, Tokyo and Osaka set up a federation of labor union.
AC Kumamoto Nichinichi Shimbun (hereinafter referred to as Kumanichi) Feb. 27
1946 Feb.-- The Nitchitsu Minamata factory starts manufacturing acetaldehyde and synthetic acid and it begins to produce vinyl chloride in October, 1949.
CH vol. 2 p. 858
1949 Apr.1 The area became Minamata city apart from Ashikita-gun because of its municipalization.
CH vol. 1 p. 658
1950 Jan.-- Nitchitsu is dissolved by Enterprise Reorganization Act. A new company made a start as Shin- Nippon Chisso Hiryo K.K. (hereinafter referred to as Shin Nitchitsu) with 400 million yen in capital.
AC CH vol. 2 p. 512
1951 Feb.20 The journal of the Shin Nihon Chisso Labor Union named Sairen is released. The monthly journal is issued till 1958. It changed the style and became a daily paper named the Nikkan (daily) Sairen News in Oct. 5, 1959, and then became the Nikkan Sairen in July 25, 1960. Then, it became Sairen on June 2, 1962.
1951 Jul.-- The labor unions of Minamata, Tokyo and Osaka join together and set up a committee. The unions' claims in common are negotiated by the committee. The Minamata Labor Union joins Federation of Unions in Synthetic Chemical Industry in August. The union has 4,400 members.
1953 Oct.1 The Shin Nihon Chisso Labor Union demands the company abolish the system of status hierarchy: unification of the different designations of the employees like company staff members or factory workers, and change the day-rate system to a salary system, and unify a system of the 55-year-old retirement. The members carry out 43-hour strike. Then, they go on 67-hour strike from 6th too.
1953 Oct.23 The Shin Nihon Chisso Labor Union begins an indefinite strike for the first time. After 27days, most of the Union's demand is accepted. This leads to the serious economic blow to the city.
CH vol. 1 p. 662 AC
1953 Dec.15 A child of 5years and 8 months old in the Detsuki area is suffering from unknown disease. Later, it turns out to be Minamata disease.
1954 Aug.1 Kumamoto Nichinichi Shimbun says the number of rats in Modo increased since all cats there died from epilepsy.
Kumanichi Aug. 1, 1954
1955 Jun.30 The organ paper for young and women's group called Chishio is first published.
1955 Dec.3 Minamata city honored Nagayoshi Maeda for his effort to inviting the Nitchitsu factory.
CH vol. 1 p. 666
1956 Apr.21 A 5-year-old girl complained of cerebral symptoms and was hospitalized in the Shin Nitchitsu's Minamata Factory Hospital. Later, three more children with the same kind of symptoms are hospitalized.
CH vol. 1 p. 666, vol. 2 p. 823
1956 May.1 Dr. Hosokawa at the Shin Nitchitsu's Minamata Factory Hospital reports that four patients with unknown cerebral symptoms are hospitalized to Minamata Healthcare Center. This is the time when Minamata disease is officially discovered. Fifty two patients are recognized this year.
CH vol. 1 p. 666, vol. 2 p. 823
1956 May.28 Minamata city, Minamata Healthcare Center, Minamata Medical Association, Minamata City Hospital, and the Shin Nitchitsu's Minamata Factory Hospital all together form the Strange Disease Management Committee of Minamata City (Minamata-shi Kibyo Taisaku Iinkai). The patients are held in a building for contagious disease patients, and the areas with high incidence of the disease are disinfected.
CH vol. 1 p. 666 vol. 2 p. 825
1956 Jul.27 Eight hospitalized patients in the Shin Nitchitsu's Minamata Factory Hospital are sent to the city quarantine hospital as possibly having Japanese encephalitis. Then they are held in the Fujisakidai Branch Hospital affiliated to the medical school of Kumamoto University on August 30.
CH vol. 2 p. 859
1956 Sept.1 Minamata city merges with Kugino-mura, Ashikita-gun. Its population became 50,461 people and the city has 10,168 families.
CH vol. 2 p. 24
1956 Nov.3 The study group of Kumamoto University releases an interim report: the disease is not contagious but possibly caused by poisoning of a kind of heavy metal.
CH vol. 2 p. 826