Volume 6 is the sixth volume of Shigurui that includes chapters 27-31.
In this volume Fujiki realises he has left the dojo undefended while Iraku and Iku set their plot to assassinate Kogan into motion.
Fujiki waits at Mt. Akiba in Kontake temple. He informed no one of Iraku’s letter, instead wanting to fight Iraku alone. A man who had previously been present at the Kengyou estate appears before Fujiki with a gun. He fires it but with luck, Fujiki correctly anticipates he would aim for his forehead, and blocks the bullet using the base of his sword. Although Fujiki kills the assassin as he flees, he realises he has left the dojo undefended. At that moment, Iraku and Iku appears on the door steps of the Iwamoto Kogan dojo.
Iraku and Iku explain to three masters and former students of Kogan at the dojo’s doorstep that they were Biwa players sent from Kengyou as a token of thanks for the martial arts displayed days earlier by Kogan. The three masters are aware of the ruse, but believe trapping them inside the inner chamber would prove easier than fighting out in the open. In the inner chamber, Kogan sits behind a veil of silk, and two of his masters sit in front while the third sits behind Iraku and Iku, apparently to ensure the lantern did not go out. Iraku senses Kogan was not of his senses given the smell of urine on his clothes. Iku proceeds to play while Iraku sings, to the enjoyment of servants overhearing; who had not noticed Mie had left their side. Iraku offers his hosts to observe Iku’s back. Not wanting to pass up the opportunity to observe the beauty of Iku, the three masters agree. Iku removes her clothes and stands naked in front of Kogan. Kogan remains expressionless, despite the burn on Iku’s disfigured breast now clearly visible. Iku turns her back to face Kogan, and at that moment, Iraku hears the sound of Kogan's hair rising on end. On Iku’s back Kogan sees a tattoo of a dragon without pupils strangling an old tiger. Enraged at the taunt, Kogan stands and injures Iku by slashing the dragons head, separating it from Iku’s skin. Everything was going as planned, Iraku would inform the authorities that Kogan took leave of his senses, had acted violently towards Kengyou’s beloved mistress, and therefore had no choice but to strike him down in self-defence. The two masters, standing between Iraku and Kogan, draw their swords. Kogan, in his state of psychosis, decapitates both masters from behind. The mistake Iraku had made was not only that Kogan is insane, but that he had been transformed into a terrible thing that did not distinguish between friend or foe, a demonic god ready to strike down anything that entered its domain.
Iraku shakes with horror as Kogan kicks the bloodied corpse of his own ally to Iraku, only for the corpse to miss Iraku and hit the ceiling. The drops of blood falling from the ceiling inhibit Iraku’s sense of sound and smell, rendering it difficult to discern Kogan’s movements. Iraku commences his impenetrable attacking stance, leaning against his sword while Kogan stands with his ultimate art, Nagare Boshi. This would mark the first time Kogan had used the stance twice against the same opponent. Iku, behind Kogan, and Iraku, in front, were both within range of Nagare Boshi.
Eleven months after Iraku was expelled, Kogan presented Fujiki with a bottle with a hole in it. Sensing this was related to the secret art, his warrior’s instinct brought him to a deserted house. Fujiki arranged some unbroken bottles before him, and realised when a man’s fingers moved at incredible speed and force, a hole could be pierced into the bottle without shattering it. Fujiki could not pierce a hole in the bottle without destroying the top half. Elsewhere, deep in the woods, Iku and Iraku encounter a group of bandits. Aware Iraku could not fight due to his blindness, Iku stands in front of Iraku, and is prepared to give her life to defend him. Iraku asks Iku to stand back as he attempts to strike at all three at once, but misses them completely and embeds his sword deep into a tree. Iraku desperately attempts to pry the sword out as the bandits draw close. With just enough time, Iraku dislodges the sword and kills all three with a single swipe, moving at a speed beyond even what Iraku himself expected he was capable of. At that moment, Iraku came back to life. At the deserted house, Fujiki finally manages to pierce a hole into the bottle using his fingers after a succession of failed attempts. The next day, Gonzaemon grants Fujiki licence to use Kogan-ryuu.
At the duelling ground, as Kogan begins to strike, Iraku counters with a manoeuvre which involved diving under his opponent and striking upwards. The manoeuvre had defeated Kogan and his Nagare Boshi. Iraku wonders why he could not hear Kogan falling to the ground but only hear the peculiar sound of wind, as well as the sound of Iku collapsing from her injury. Mie appears and as Kogan turns to face her, he envisions Mie in a wedding gown, and states he had no words to express how happy he was on this auspicious day. He states Mie had become beautiful. The moment between father and daughter was cut short however, as Iraku drives his sword through Kogan’s back. Iraku sees Kogan had already lost half of his face from his first strike, and the peculiar sound of wind was actually the sound of the ancient tiger choking on his own blood. Before his daughter’s eyes, Kogan collapses and dies. In shock, Mie faints.