Akashi Castle is a Japanese castle in Akashi, Hyōgo Prefecture, Japan. This castle was constructed by Ogasawara Tadazane as his own castle from 1617 to 1619 to watch over the western lords, by the order of Tokugawa Hidetada, on Mount Akamatsu. It is known Miyamoto Musashi helped too as he was invited by Ogasawara Tadanao as a "Construction Supervisor". The castle was built in one year, which was a relatively short amount of time.