[3] The arsenal also produced licensed Mauser style rifles based on the Gewehr 98 for the military of Siam (now Thailand).

[7][8] After the First World War, the Imperial Japanese Army Institute of Science was established within the Koishikawa arsenal.

In 1937, the Number Nine Research Laboratory was established as a breakaway unit from this station.

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.