Kubikiribōchō

The Decapitating Carving Knife is shaped like a giant butcher knife. It has a circle cut out of the top and the semicircle near the handle, which, as demonstrated by Suigetsu, seem to fit the sword's purpose of decapitation aptly, and gives something to wrap a back strap around. Its handle is detachable; Suigetsu is shown screwing it off before traveling and reattaching it for combat. Suigetsu, despite being well-trained, notes that the heaviness of the blade can tire him out easily.

This giant blade was used by Zabuza during his membership as one of the Seven Swordsmen of the Mist. After defecting from Kirigakure, he continued to use it up until his death. It was left beside his grave until Suigetsu took it for himself three years later. In the manga, Suigetsu simply takes the blade from Zabuza's grave. In the anime, after Zabuza's death, the blade was stolen by Tenzen Daikoku, a crime boss who lost many men to the blade, as a trophy, and was used by one of his bodyguards until Suigetsu took it forcefully.

During Taka's fight with Killer Bee, Bee cuts into the Decapitating Carving Knife, damaging it. When later fighting the Fourth Raikage, the Raikage snaps the blade along the same cut-line that Bee created. Despite being cut in half, Suigetsu continues to use the blade, which now resembles a cleaver. The sword is taken from him when he is captured by samurai. He tries to locate the sword when he escapes, but cannot find it anywhere. Shortly afterwards, the sword is shown having been returned to a revived Zabuza.

Abilities
Besides being used for kenjutsu, the blade has a unique power to reform itself from the iron harvested from its victims' blood. This ability makes the carving knife very useful and ideal for battle as well as indestructible.

Trivia

 * This is the only one of the seven blades of the Swordsmen of the Mist shown so far to not have any special abilities.