Originally called Ozakajō, it is one of Japan's most famous castles, and played a major role in the unification of Japan during the sixteenth century of the Azuchi-Momoyama period. Osaka Castle is situated on a plot of land roughly one kilometer square. It is built on two raised platforms of landfill supported by sheer walls of cut rock, using a technique called Burdock piling, each overlooking a moat. The central castle building is five stories on the outside and eight stories on the inside, and built atop a tall stone foundation to protect its occupants from sword-bearing attackers.
The Castle grounds, which cover approximately 60,000 square meters (15 acres) contain thirteen structures which have been designated as Important Cultural Assets by the Japanese government, including the Toyokuni Shrine, dedicated to Toyotomi Hideyoshi.
The castle is open to the public, and is easily accessible from Osakajōkōen Station on the JR West Osaka Loop Line. It is a popular spot during festival seasons, and especially during the cherry blossom bloom (hanami), when the sprawling castle grounds are covered with food vendors and taiko drummers. The large indoor arena Osaka-jo Hall is also located within the grounds of the castle park.