The Tekko-kagi ("hand claws")

Predating X-Men's Wolverine by hundreds of years, Ninjas would use the Tekko-kagi claws to guard against sword attacks, allowing them to swipe and potentially knock the sword from an assailant's hands.
Ninjas also used claws offensively against their opponents with devastating results.
Typically made from aluminum, steel, iron or wood, Tekko weapons are believed by martial arts historians to have originated when the Bushi in Okinawa, Japan began wielding the steel shoes of their horses as a means of self-defense against assailants.
Note: Bushi, a term for Japanese Samurai seen in the term Bushidō.