Koishikawa arsenal

The Koishikawa arsenal (小石川工廠), formally Imperial Japanese Army Tokyo Arsenal (日本帝国陸軍東京砲兵工廠) was an arsenal in the Koishikawa area of Tokyo, on the grounds of today's Tokyo Dome City and the Koishikawa Kōrakuen Garden. It was located on the ground of the former residence of the Prince of Mito.

The arsenal was inaugurated in 1871, soon after the Meiji restoration. One of its main early productions was the Murata rifle, the first locally-produced Japanese rifle. As of 1893, it was producing about 200 rifles and 200,000 cartridges daily. The arsenal was especially active between the two World Wars, as the Arisaka was produced there.

The arsenal also produced airplanes after World War I for the Japanese army, and also for the Imperial Russian Army, which placed an order for 10 airplanes before 1916.

Discipline and organization at the arsenal are thought to have been extremely strict, leading to the development of labor disputes in which the Koishikawa arsenal took a leading role in Japan.

The arsenal suffered considerable destruction during the Great Kantō Earthquake on 1 September 1923. Complete reconstruction was deemed too expensive, so that the arsenal was transferred to Kokura in Kyūshū (小倉工廠) in October 1935, after 66 years of operation.