Originally a gorgeous castle built by Toyotomi Hideyoshi in 1583, Osaka Castle was destroyed by the Shogun Tokugawa Ieyasu during the 1615 Siege of Osaka. In 1620, the Shogunate commenced the rebuilding of Osaka, creating a larger, more magnificent castle over top of the old one, completely reclaiming and removing any vestiges of the Toyotomi clan. The ishigaki stone walls were rebuilt about twice as high as those of the Toyotomi period, reaching a record 30m, and ten particularly large stones were sourced and installed in the castle entrances as a show of authority. A five story tenshu, 11 three-story yagura watchtowers and two double story yagura were constructed around the Honmaru, all linked via corridor-like tamon-yagura. The three-story Fushimi Yagura and 13 double-story yagura interconnected by earthen walls were constructed in the Ni-no-maru. Osaka Castle’s tenshu was reconstructed in concrete in 1931.