A Boruto episode centered on Tsubaki Kurogane, whose investigation of a string of sword attacks reveals the culprit is Sazanka, a former fellow disciple from the Land of Iron who fell into obsession with raw strength. Tsubaki must confront her guilt over his descent and settle their duel.
Tsubaki wakes from a dream of her old training days with Sazanka in the Land of Iron, puzzled that the memory has resurfaced. Team 15 visits a merchant recovering in the hospital after a bandit assault, but the sound of Tsubaki handling her blade sends him into a panic, shouting that samurai are hunting him once more, and a nurse ushers the team out. Certain the attacker was a swordsman, they search the scene and find neatly severed bamboo that Tsubaki reads as the work of a master.
The cut jogs her memory of Sazanka, once a prodigy who trained to earn the right to wield Mifune's blade Kurosawa, the prize rumored to await the retirement of its owner. At the Lightning Burger, Wasabi reports a fresh attack, and Tsubaki finally voices her suspicion. She explains that Sazanka forsook his path in pursuit of power alone, was caught trying to steal Kurosawa, and cut down his fellow trainees to escape. Confident she can face him, she drills alone through the night.
Team 15 baits the bandits into a trap and rounds up most of them, but the gang has hired Sazanka as their guard. He slashes Tsubaki before she can even unsheathe her weapon, shrugs off Namida's technique, and the team pulls back. Tending her wounds, Wasabi presses her on why she froze, and Tsubaki asks to be removed from the mission, admitting she blames herself for the man Sazanka became after she beat him by luck in the tournament that changed him. Her teammates remind her how far she has grown since joining the Leaf, and her resolve returns.
In the rematch Tsubaki singles out Sazanka, who insists a blade exists only to cut and dismisses her progress as false training. She answers his flawless offense with her Secret Sword: Snowstorm Beheading, and though he shears through it, she rejects his demand that she concede, crediting the strength she has drawn from friends who trust her. When their swords meet again, Tsubaki cuts him down, saddened by the outcome even as Sazanka concedes her power.

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The chapter deepens Tsubaki Kurogane's arc within Team 15, tying her growth in Konoha to her samurai roots and her signature Secret Sword: Snowstorm Beheading. It closes on a lighter beat as a recovering Tsubaki teases Wasabi and Namida while they help her get around.
In The Rusty Sword, Boruto episode 231, Tsubaki Kurogane hunts down her old training partner Sazanka, who has been attacking people while working as a hired guard for bandits. After an initial defeat leaves her shaken, Tsubaki fights him again with her Secret Sword: Snowstorm Beheading and finally cuts him down, though the win leaves her saddened rather than triumphant.
Sazanka is a former fellow disciple of Tsubaki Kurogane from the Land of Iron who once trained to earn the right to wield Mifune's sword Kurosawa. He fell into an obsession with raw strength, was caught trying to steal Kurosawa, and cut down fellow trainees to escape before turning up as a hired blade guarding bandits.
Secret Sword: Snowstorm Beheading is Tsubaki Kurogane's signature technique, which she uses against Sazanka in The Rusty Sword. Sazanka shears through it during their first clash, but Tsubaki relies on it again, backed by the strength she draws from her friends, when she finally cuts him down in their rematch.
Tsubaki blames herself because she once beat Sazanka in a tournament by luck, and that loss is what pushed him toward obsessing over raw power. Her guilt makes her ask to be pulled from the mission until her Team 15 teammates remind her how much she has grown since joining the Leaf.
Team 15 baits the bandit gang into a trap and captures most of them, but their hired guard Sazanka slashes Tsubaki before she can even draw her weapon, forcing the team to pull back. After recovering her resolve, Tsubaki returns to defeat Sazanka in a final duel.
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View on FandomThis content is original writing by Daddy Jim Headquarters based on the Naruto anime series, manga, and official materials. Episode and chapter references are cited where applicable.
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