Genbu [玄武; genbu, literally "black turtle"], more commonly known as the Island Turtle (島亀; shimagame, lit. "island turtle") is a gigantic and ancient turtle that resides in the Land of Lightning. Since its founding and taming by Yokoshima Kurahama, it has been cared for by Kumogakure and serves as a training ground for the Kumo ninja. It is described as a moving fortress and size is so great that it can host other large animals as well as other natural and man-made structures. The turtle's shell, the "island", has an accumulation of plant life that has grown on it. Described as a paradise by those who have never seen it, Genbu is anything but that to humans, with signs of death and battle everywhere and large, ferocious animals populating the island. The Falls of Truth can also be found on the island. The island is protected by a giant squid, which attacks anything that approaches. In addition, the island can move through the surrounding bodies of water freely, making it impossible to find without air reconnaissance. The turtle itself is incredibly large, rivaling the Ten-Tails in size. It is mostly grey in color, with spikes protruding from its shell and with a blue underbelly. Its shell is extremely sturdy, being able to withstand attacks of powerful techniques and, according to Kurahama, could even house a tailed beast; it is implied that its underbelly is less so, but still strong enough to handle powerful explosions without sustaining any damage.