Tekagi-shuko are specialized iron knuckles, used mainly as a tool for climbing, however they could be utilized as a weapon if necessary under emergencies. The shuko are comprised of two metal hoops, tied together with a strong leather strap. One of the hoops is placed around the wrist and the other around the hand, and the hoop that is placed around the hand has sharp spikes or hooks to aid climbing. Shuko are a special tool of Togakure ryu and this school contains specific kata designed around the use of the shuko. However, within Bujinkan the shuko are also used within other schools, such as Koto ryu, Gyokko ryu and Shinden fudo ryu.