Osaka Castle (大坂城 or 大阪城,, Ōsaka-jō?) 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.
Located near the center of Osaka Prefecture, Osaka Castle was built on flat land on the Uemachi Plateau, on the former site of the Ishiyama Honganji Temple. In 1583, Toyotomi Hideyoshi completed construction of this magnificent and splendid castle, which took three years in total. The castle fell in 1615 during the fighting known as the winter siege and summer siege of Osaka. Later, Tokugawa Hidetada rebuilt and greatly remodeled the castle. However, most of this remodeled Osaka Castle was destroyed during the Boshin War. Today's castle was restored in 1931, based on paintings of the original on folding screens. Together with those in Nagoya and Kumamoto, Osaka Castle numbers among Japan's three most important castles.