Osaka Castle was the base of the then feudal government in Edo, present Tokyo, to control Western Japan. Tokugawa feudal government stored the gains from many places under direct control in Western Japan into this Kinzo. These gains were the profit from foreign trade through Nagasaki, gold and silver mines mainly in Kyushu and Ikuno, special agricultural products and so on. There had been an old Kinzo in Osaka Castle though, as one Kinzo had not been enough, this Kinzo was additionally built in 1751.
The old one was reduced to ashes about 100 years ago.
The new Kinzo is fireproof construction with elaborate security installations, such as the thick stone paved floor and triple doors. The gold and silver coins in the Kinzo were not only for daily use but also as war funds.
This is on the list of an important cultural asset.
License tour guide, travel consultant.