Kubikiribōchō

The is a massive broadsword shaped like a giant butcher knife, earning it the title of. 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.

History
Although this giant blade was said to have been used by Mangetsu Hōzuki, it became the trademark weapon of Zabuza during his time as one of the Seven Swordsmen of the Mist. After defecting from Kirigakure, he continued to use it up until his death, where it was left beside his grave until Suigetsu took it for himself three years later.

During Taka's fight with Killer B, not only did the Kumogakure jinchūriki wield the blade momentarily, he managed to slice into a portion of the blade, weakening it considerably. When later confronting the Fourth Raikage, A struck the blade along the same cut that B had created, splitting it into two.

Despite being halved, Suigetsu continued to use the blade, which now resembled a cleaver, knowing it has regenerative capabilities, but the sword was taken from him when he was captured and imprisoned by the Land of Iron's samurai. However, in spite of trying to locate the sword after his escape, he was unable to find it anywhere. Shortly afterwards, during the clash between Kabuto Yakushi's troops and the Third Division of the Allied Shinobi Forces, the sword is shown having been returned to a reincarnated Zabuza, who starts striking down numerous enemies with it in order to reform the broken blade.

Nevertheless, the sword is only fully restored after Zabuza wounds Kakashi Hatake, who had been immobilised by Haku. Later, with Zabuza's defeat, Kakashi took the blade into his possession and has shown great skill in using it in battle. While doing so, he flowed lightning-natured chakra through the sword to enhance its cutting power, similar to the Sword of Kusanagi: Chidori Katana technique of his former student. When Kakashi saves Naruto Uzumaki from Tobi, the sword is not seen in his possession.

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, as demonstrated through Suigetsu Hōzuki's use. 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. However, despite being well-trained, Suigetsu noted that the heaviness of the blade could still tire him out easily; a problem Zabuza Momochi didn't have.

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

 * The name "Kubikiribōchō" translates, literally, as "Decapitating Carving Knife", the first part, "首斬り", means "Decapitation" (as a method of execution), and "包丁 refers to a large cooking knife, or cleaver.
 * 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.