is a Japanese castle in Chūō-ku, Osaka, Osaka Prefecture, Japan. 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.