Japanese Kabutowari/Hachiwari , Samurai/Ninja - Japan - 18/19th century (late Edo period). The Kabutowari/Hachiwara /helmet splitter was used to pierce a Samurai's harness or to parry an enemy's melee attack. Because of its sharp point and narrow design, it was capable of to pierce a weak spot in the harness. The hook at the lower end also allowed for breaking or severely damaging the sword of an enemy, while the same hook could be used to pry open a Samurai's helmet (composed of loose plates) in order to stab the enemy in the head.
The hachiwara was worn on the right side of the body and was designed to be drawn by the left hand. It could parry attacks, and the name means "helmet breaker", although it is doubtful that it is strong enough to actually break a helmet. However, it is possible to get the hook under someone's helmet and apply enough pressure to pop out one of the metal plates or force the opponent's head to the side.
length 20 1/2 in., blade from the tsuka/handle 10 3/4 in.