1496 The Buddhist Sect Jōdo Shinshū founds a monastery on the ruins of the old Naniwa Imperial Palace, in the immediate vicinity of the current castle. In time, it becomes a great Buddhist temple, known as Hongan-Ji (or Ishi-Yama Hongan-Ji)
1570 The Shogun (the supreme military authority of the country) Oda Nobunaga begins the siege of the temple.
1580 The monks of Hongan-Ji surrender and the temple is demolished
1583 After the death of Oda Nobunaga, Hashiba (Toyotomi) Hideyoshi takes over political control and begins the construction of the castle, which will become the permanent residence of the country's leaders. For this, Ikkou-ikki temple is chosen in the monastery complex Ishi-Yama Hongan-Ji. Azuchi Castle, the residence of Oda Nobunaga, serves as a model. The plan includes the main tower five levels up and three other underground levels
1585 The main tower is built. Toyotomi continues to expand and fortify the castle, making it harder to conquer
1598 The castle construction is completed. Hideyoshi dies. Osaka Castle belongs to his son, Toyotomi Hideyori
1600 Tokugawa Ieyasu defeats Hideyori's troops in the Battle of Sekigahara and forms his own givern (bakufu) in Edo
1614 Tokugawa attacks Hideyori in winter, beginning Osaka Castle siege [2]. Toyotomi's troops, though approximately two times less, managed to withstand the Tokugawa army (about 200,000 soldiers) and protect the outer wall of the castle. However, Tokugawa weakened the castle's protective capability by covering its outer ditch with the earth
1615 Tokugawa attacks Osaka Castle for the second time. The castle falls and the Toyotomi clan disappears
1620 The new shogun, Tokugawa Hidetada, began the reconstruction and fortification of the castle. He builds a new tower and attributes the construction of the outer wall to the samurai clans. The wall erected in the 1620s exists to date. Many stones brought by the samurai keep the symbol of the families that built them
1660 Due to electrical discharge, the gunpowder explodes, causing fire in the castle
1665 Due to electrical discharge, the main tower is burnt
1843 After decades of oblivion, the castle is repaired. The money for repairs is gathered from the inhabitants of the region
1868 A large part of the castle is burned as a result of the civil war in connection with the Meiji Restoration. Under the leadership of the Meiji government, Osaka Castle is turned into barracks for the new Western-style army
1928 After a successful campaign led by the mayor of Osaka in order to raise the necessary money, the castle's main tower is rebuilt
1945 Air strikes damage the newly rebuilt tower
1995 The City Hall of Osaka adopts another reconstruction project with the intention of bringing the main tower back to its splendor of the Edo period
1997 Restoration works are completed. The castle is a reproduction in concrete (including the accent) of the original, although the interior does not bear any resemblance to a Japanese castle