"Zabuza's Blade" (再不斬の大刀, Zabuza no Daitō) is episode 115 of the Naruto: Shippūden anime.
Sometime in the past, Sasuke had told Suigetsu Hōzuki, a prisoner of Orochimaru's, that he would free him one day. After having killed Orochimaru, Sasuke makes good on his promise and frees Suigetsu from his water tank. After being freed, Sasuke tells Suigetsu that he is the first member to be added to a team he is forming, along with Karin of the Southern Hideout and Jūgo of the Northern Hideout. Suigetsu shows no desire to join Sasuke's team at first, but decides to join under the condition that Sasuke help him find Kubikiribōchō, the sword of Zabuza Momochi, who was one of the Seven Ninja Swordsmen of the Mist, since it was Sasuke's squad that defeated Zabuza.
Sasuke and Suigetsu head to the Land of Waves, where Sasuke notices that the name of the bridge is called the Great Naruto Bridge. Suigetsu asks whether Zabuza was tough, and Sasuke recalls his first encounter with Zabuza, as well as when Zabuza trappedKakashi inside of his Water Prison Technique. Sasuke is snapped out of his reverie by Suigetsu and merely crosses the bridge and enters the village, where they nearly get into a fight with a rude villager. After heading to Zabuza and Haku's Grave, they discover that Kubikiribōchō, which Kakashi had buried there along with Zabuza, is missing. After heading to a village restaurant, Suigetsu notices all the girls there fawning over Sasuke and tells them that Sasuke is looking for the blade, prompting them all to tell him that Tazuna knows its location. Sasuke remembers meeting him and tells Suigetsu that Tazuna was the bridge builder who built the Great Naruto Bridge. However, when they get to Tazuna's house, they discover that both he and his grandson Inari left for the Land of Lightning and would not return for a year; however, a worker there does tell them that he knows the whereabouts of Kubikiribōchō, and that it is in the possession of a corrupt boss named Tenzen Daikoku.
In the village, Suigetsu and Sasuke come across the rude villager once more and Suigetsu threatens him to give up Tenzen's location. That night, Sasuke infiltrates the castle and points his sword at Tenzen, telling him that his name is Suigetsu and that he would attack tomorrow with an army, and to have tens of thousands of men ready. As Tenzen rallies his troops, Sasuke merely tells Suigetsu that there is a rival group clashing against Tenzen and that he should use the opportunity to seize Kubikiribōchō. Sasuke makes a wager with Suigetsu in which they deal with Tenzen's men without killing any of them and enters into the fray, defeating one half with ease. As the other half approaches, Sasuke disappears, leaving Suigetsu to deal with them. Suigetsu is able to easily defeat them and heads inside the mansion, only to be bisected by Tenzen's Bodyguard, who wields the Kubikiribōchō.
Utilising his Hydrification Technique to liquefy and rejoin his bottom half, Suigetsu tells them that he cannot be harmed by blades. He then uses his Water Release: Great Water Arm Technique to pry Zabuza's blade out of the bodyguard's arms, sending the bodyguard flying. Suigetsu wishes to kill Tenzen as Tenzen has been spreading rumours that he was the one who killed Zabuza, only to be interrupted by Sasuke, who convinces Suigetsu not to kill him. As Suigetsu destroys the pillars around the house to give Tenzen a chance to live, Tenzen demands to know whether this Sasuke is the very one who killed Orochimaru, surprising Suigetsu that the word has already spread. As the duo leave the Land of Waves, Suigetsu realises that Sasuke knew the blade had been taken and had set up the whole thing with Tenzen's army in order for Sasuke to test his strength. They then head to the Southern Hideout, where Karin is located, who manages to knock a man out after stating that Orochimaru's death does not grant him the right to do whatever he pleases. However, she quickly senses a powerful and frightening chakra nearby.