Osaka Arsenal Loading Gate
The gate across the moat once served as a delivery entrance for the Osaka Arsenal (Ōsaka Hōhei Kōshō), a sprawling complex of munitions factories located on the eastern side of the castle. Between 1870 and the end of World War II, the arsenal produced weapons and equipment for the Imperial Japanese Army, including much of its artillery. Raw materials could be brought in directly from nearby seaports via the area’s many rivers and canals.
Even during the relative peace of the Edo period (1603–1867), the district on this side of the castle was used to produce and store weaponry. A gunpowder refinery exploded in January 1868 during the Meiji Restoration, when the forces of the Tokugawa shogunate abandoned the city, and days of chaos and looting ensued. The massive explosion was likely set off by fires that also destroyed large parts of the castle.