The Kubotan keychain was originally based on a small bamboo weapon called the hashi stick, an invention by Kubota’s father Denjiro. Its popularity grew from 1969 to the 1970s when Kubota, at the request of California State Senator Edward M Davis, former Chief of the Los Angeles Police Department, created the weapon and began training female officers in its application.
The actual Kubotan is typically no more than 14cm (5.5in)-long, so easily concealable in the hand, and about 1.25cm (0.5in) in diameter, slightly thicker or the same size as a marker pen. The material is usually a hard, high-impact plastic such as Lexan. The body of the Kubotan is lined with six round grooves with a screw eye or swivel and split ring attachment at one end for keys. Applied as a weapon, some of its uses are similar to that of the yawara stick or koppo stick. The principal targets in self-defence include bony, fleshy and sensitive parts such as knuckles, forearms, the bridge of the nose, shins, stomach, solar plexus, spine, temple, ribs, groin, neck and eyes. The Kubotan is usually held in either an icepick grip (for hammerfist strikes) or forward grip (for stabbing, pressure point attacks and seizing). Common uses include hardening the fist (fistload) for punching, attacking vulnerable parts of an assailant’s body and gaining leverage on an assailant’s wrist, fingers and joints. With keys attached, it can function as a flailing weapon. As a pressure point weapon it can attack any point a finger can, but with greater penetration because of the smaller surface area at the ends.