Sky Ship (空(から)の船, Kara no Fune) is the 568th chapter of Gintama series. Battle against Hankai comes to an end and the reason for Sakamoto to wield a gun instead of a sword is revealed.
Sakamoto shoots Hankai on Nobunobu's cue, destroying Hankai's core. With the robot defeated, the Kaientai's fleet is freed from its control, thus enabling them to keep Kairinmaru afloat by attaching the smaller ships to it. In the meantime, the crew on the main ship rushes to the core room to fix the damages. While Nobunobu and Mutsu observe Sakamoto and the crew, the former notes the differences between Hankai's soldiers and Kaientai's. Pointing out how neither the Kaientai leader nor his followers abandoned each other despite the difficulties, Nobunobu tells Mutsu the rarity of Sakamoto's leadership and how his pales in comparison because of his way of ruling.
Mutsu ponders for a moment before comparing a ruler to an empty vessel that achieves nothing when left alone; it needs a crew in order to travel to a common destination, thus forming an alliance. Stating that Nobunobu is like an empty vessel that travels alone by riding on his own people, he is bound to fail no matter how powerful he is. The retainer then asks where the storm-battered ship is heading to in its current state and in the midst of a battle, to which Mutsu merely respond that it is just wandering around picking up lost wanderers, including Nobunobu. It will eventually lead them to a future that brings everyone laughter. Nobunobu gets up and leaves, thinking about how strong and encompassing Sakamoto is. The latter quietly watches Nobunobu leave and look at his right arm, revealing a nasty scar along the wrist and forearm. Believing that this is his only way to battle, he begins to recall the origin of the scar.
During the Joui Wars, an injured Sakamoto is carried on a stretcher with worried soldiers around. Takasugi arrived shortly and questioned everyone on his injuries. One of them begins to explain that a beam sabre-wielding swordsman attacked Sakamoto while they were trying to save the enemy soldiers. Upon hearing, Takasugi chastised Sakamoto on helping enemy soldiers, adding that he can never be a samurai due to his severe hand injury that deemed sword wielding impossible, which Sakamoto agrees. A nearby Gintoki beg to differ, stating that Sakamoto's way of fighting isn't merely swinging around with a sword. Both Gintoki and Takasugi then went on to find Sakamoto's attacker for revenge, with the former eventually finding him. This echoes the present where the Yorozuya-Kihetai, led by Gintoki, comes face to face with the said swordsman on Rakuyou.
- Mutsu: (To Nobunobu, on his rule) A ruler is like a sky ship. Alone, it ain't even gonna move. But with people on it, it can move and go to the place everyone wishes to go. So the crew can't abandon the ship, and the ship's gotta protect the crew from the stormy seas. Yer ship couldn't hold up against that weight. So you made people inta ships and rode alone on top 'a them. No matter how huge yer ship is, an empty ship with just one guy on it ain't gonna go anywhere.
- Gintoki: (On Sakamoto) He ain't dead. A samurai's more than a guy that swings a sword around. Cutting down enemies ain't the only part of a war. Sakamoto Tatsuma's war ain't some petty war you can clean up with a broken pole.