The Kubotan (sometimes erroneously spelle as Kubaton or Kobutan) self-defense keychain, is a close-quarter self-defense weapon developed by Soke Takayuki Kubota. It is essentially a derivation of the Yawara stick, usually 5.5 inches (14cm) long and 0.56 inch (1.5 cm) in diameter, slightly thicker or the same size as a marker pen. Attached with a keyring for convenience and concealment, the kubotan appears as an innocuous key fob to the untrained eye.