Osaka: From Castle to Commerce

From Castles in Japan, by Morton S. Schmorleitz (Tuttle, 2011), Kindle Loc. ~1017ff:

After 1615, Osaka was no longer an important military center, but became one of the three chief cities under direct control of the shogunate. (Note: The others were Edo and Kyoto.) A 10-year restoration of the castle was begun in 1620, but the donjon was struck by lightning and destroyed in 1665, During the remainder of the feudal period the castle grounds served as the seat of local government and for the garrisoning of troops.

As time went on, Osaka became the most important commercial center in the country. Hideyoshi had encouraged merchants from the fortified city of Sakai to move to Osaka and supply the castle and the town, which was rapidly growing. After Ieyasu took over, more merchants came in from Fushimi. Although the daimyo of the Ou and Kanto districts built warehouses in Edo to store and distribute their revenues of rice, most of the feudal lords converted rice into cash at Osaka. Soon there were some 500 to 600 warehouses in the city which not only processed food, but many other forms of merchandise as well.

During most of the Tokugawa period the city remained a peaceful but busy commercial center. In 1837, however, the peace was broken by a riot led by one Oshio Heihachiro. Many fires were started, and homes and buildings (especially of the rich) were destroyed before troops garrisoned at the castle could bring the situation under control. This riot was an overt expression of national dissatisfaction with the government, a malcontent feeling that eventually led to the downfall of the Tokugawa regime. During the 1850's and '60's the castle was used to receive foreign diplomats when the shogun was in residence there.

In September 1868 part of the castle was burned by Tokugawa troops as they retreated before troops loyal to the emperor during the civil war that brought about the Restoration. In 1931 a donjon of ferro-concrete material was constructed atop the 45-foot foundation of the former keep, and the castle grounds were opened as a public park. During the Pacific War troops were again garrisoned on the castle grounds. Although the new donjon was not touched by the war, four turrets were destroyed. Today the castle grounds are again used as a public park, and the donjon contains exhibits relating to the history of old Osaka including a display of archeological interest and a model of the castle showing what it was like at its prime.