The Osaka Artillery Arsenal /a.k.a. Osaka Army Arsenal; 大阪砲兵工廠/ was established on the premises of the Osaka Castle in 1870. For the newborn Meiji government, to establish armament modernization and weapons self-sufficiency was one of the highest priorities. Masujiro Omura of Hyobu Taifu focused attention on the superiority of the Osaka Castle as a military base, and proposed the idea of basing central military organizations in the Osaka Castle, though quite a lot argued to use the capital, Tokyo as the base. On November 5, 1869, Omura became a victim of an assassin and was killed. However, Omura's petition for installing the Naval and Army Academy and establishing production factories for guns, ammunition and explosives in Osaka, which could be a central location for sea and land transport was adopted to some degree.
In February 1870, Zoheishi (weapons-manufacturing office) was placed in the War Ministry, and in March of that year, they decided to use the vacant lot of the Sannomaru rice warehouse located in the northeastern district of the Osaka Castle as the site for the office. This was the beginning of the Osaka Army Arsenal. Machines and workers were transferred from Nagasaki Iron Works that was under control of the Tokugawa shogunate, and some machines came from Tokyo Sekiguchi Seizosho (later Tokyo Army Arsenal) to start operations.
The Army Ministry defined, in Article 1 of the Army Arsenal Ordinance (Hohei Kosho Jorei) (No.79 Notice of the Army Ministry on October 10, 1879), army arsenals shall be placed in Tokyo and Osaka, and in Article 2, that Tokyo Army Arsenal shall hold a small arms factory, a gun factory, a bullet factory, a cannon repair center and an explosive factory, and the Osaka Army Arsenal shall hold a cannon factory, a bullet factory, an armored car factory, a bullet factory and a gun repair center. The Osaka Army Arsenal developed as a production center for weapons, mainly cannons and bombshells.
The Satsuma Rebellion, the Sino-Japanese War (1894-1895), and the Russo-Japanese War (1904-1905) increased the importance of the Osaka Army Arsenal both in name and in reality. Their premises became larger and the production facilities were improved.
Osaka Artillery Arsenal, 1914
In the disarmament period after the First World War, the Army Ministry organizationally integrated both army arsenals in Tokyo and Osaka under an armory ordinance (imperial ordinance No. 83 on March 30, 1923), and the Osaka Army Arsenal changed its name to the Armory Osaka Arsenal of the Army Ministry (Rikugun Zoheisho Osaka Kosho). In the Showa era, when the Sino-Japanese War intensified, the arsenal rapidly increased production.
The number of employees at the armory exceeded 60,000 and it became one of the largest military armories. However, the huge factory was losing its production capability due to the shortage of workforce and materials towards the end of the war. The crisis was covered by forcibly-collecting workers and student workers, but Japan army's numerical inferiority continued. In 1945 downtown Osaka often became the target of intensive aerial attacks. Fortunately, however, the Osaka Army Arsenal received only slight damage.
Then the fatal day came. Shortly after noon on the 14th of August, a large formation of B29 bombers arrived and attacked the Osaka Army Arsenal. It was the last large attack, just one day before the last day of war, so the Osaka Army Arsenal was relentlessly bombed and 90 percent of its facilities was destroyed. It is said that workers other than air defense members had evacuated the premise at the sounding of the air-raid alert, so the number of deaths inside the premise was reported to be 382 people; however, the total number of casualties in the surrounding areas is unknown.
In this manner, the 75 year history of the Osaka Army Arsenal came to an end. The site was later reborn as the Osaka Business Park and the Osaka Castle Park. With many high-rise buildings, the ancient weapons production site is now a center for business and entertainment.
