The Kubotan (sometimes erroneously spelled as Kubaton or Kobutan) self-defense keychain is a close-quarter self-defense weapon developed by Takayuki Kubota. It is essentially a derivation of the yawara (柔?) stick, usually 5.5 inches (14 cm) 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, although it may be considered an offensive weapon in some jurisdictions.