Located in the Nishinomaru Garden of Osaka Castle, the Enshogura is a stone gunpowder storehouse built in the Edo period to store gunpowder. It was built in 1685 under the direction of Tsuchiya Masanao, who was the lord of Osaka Castle. The building is constructed entirely of granite, from floor, walls, ceiling, and beams, with walls reaching a thickness of approximately 2.4 meters. The roof is filled with soil for fire resistance, durability, and waterproofing. Such an all-stone gunpowder storehouse is unique in Japan and extremely rare. The reason for the construction of the gunpowder storehouse is that in 1660, lightning struck the earthen storehouse at the Aoyaguchi entrance of Osaka Castle, causing a huge explosion and extensive damage to the castle and its surroundings. Learning from this accident, the Shogunate aimed to construct a safer and more durable gunpowder storehouse, and the present Flaming Powder Storehouse was born. Later, in 1953, it was designated as a National Important Cultural Property, and in 1959, the interior was restored to its original state.