Kubikiribōchō

The Kubikiribōchō (首斬り包丁; lit. "Decapitating Carving Knife") is a massive broadsword shaped like a giant butcher knife, earning it the title of "seversword" (断刀, dantō). Like the other weapons belonging to the Seven Ninja Swordsmen of the Mist, the sword is passed down from generation to generation amongst the group's members.

Appearance
The blade itself has two cut outs, a circle close to the top and a semi-circular one nearer the handle, that aptly fit the sword's purpose of decapitation. The latter notch allows a strap to be wrapped around the weapon, making it easier for the user to carry. Its extremely long handle is also detachable to further aid transportation and then reattached when required for combat. The blade itself is quite heavy and can easily tire out a person, something its current wielder has managed to overcome.

Abilities
Like the other weapons employed by the Seven Ninja Swordsmen of the Mist, the sword possesses a unique power, this being its ability to reform itself using the iron harvested from the blood of its victims. This regenerative process takes place almost instantaneously and is capable of bringing the weapon back to its original condition no matter how severe the damage is, from a simple chip or nick to a complete separation of over half the blade.

Trivia

 * In the manga, Suigetsu simply retrieves the blade from Zabuza's grave. In the anime, however, some time after Zabuza's death, the sword was stolen by Tenzen Daikoku: a crime boss who lost many men to the blade. It was kept as a trophy and was used by one of his bodyguards until Suigetsu forcefully took it