Kabutowari, The Samurai Helmet Splitter

The samurai ban on carrying swords in public revived the popularity of kabutowari

Kabutowari, also known as Hachiwari (kabuto being a helmet, hachi referring to the helmet bowl or the skull, and wari meaning to break) were forged steel or cast iron truncheon-like weapons carried as a side-arm and used by samurai to parry, catch and even break swords in combat, rather like a heavy duty jitte (also known as a Jutte). The name of the device translates to "Helmet Splitter" but it is highly unlikely they would have been used for that purpose as samurai kabuto helmets were, in most instances, far too strong. The amount of force required to smash a Zunari Kabuto, the type of helmet seen in the background of the photograph below, or a Suji Kabuto, being made of curved, triangular plates riveted together to form the helmet bowl, would have been too great. Likewise, the story that the kabutowari were used like a can opener to pry open armor is also completely fiction.