The octopus stone, Taiko-ishi è¸ç³ (also called "Drum Rock") is a large stone at Osaka Castle in Japan. The stone is near Sakura Gate.
It is one of the largest of several megaliths at the castle (by face area), at 5.5ÃÂ11.7 meters and over . Its name is derived from the octopus shape visible on its lower left corner.