This edition follows in close detail—while fixing the boundary between history and legend—how a single Bandō warrior became the uncanny "flying head" and then turned into a god who guards Edo. First, history and the uncanny must be separated. The revolt itself is conveyed by the near-contemporary Shōmonki, which records in classical Chinese the private feud beginning in 935, the subjugation of the Kantō provincial seats, the proclamation as New Emperor, and the death in battle in 940. But here there is no marvel of a flying head. The supernatural story of a head that would not rot, cried out, and flew appears only centuries later, in the Nanboku-chō-period Taiheiki, with anecdotal relays such as the Konjaku Monogatari-shū in between. It is in this later stratum of legend that Masakado is told as a "yokai." The story of the curse around his head mound is newer still. The dread transmitted at the Masakado Grave-Mound at Ōtemachi—"move it and it curses"—is a modern urban legend, layered onto events that occurred in the heart of the city in the Taishō and Shōwa eras: the deaths of those involved in building the Ministry of Finance's temporary office after the Great Kantō Earthquake, and the bulldozer accident during the Occupation. The factual events and the interpretation that attributes them to Masakado's curse must be carefully separated. The path of deification, on the other hand, reaches back into the medieval age. In the second year of Enkyō (1309), the Ji-sect holy man Shinkyō Shōnin, who attributed a plague to Masakado's curse, pacified the spirit and added it to the enshrined deities of Kanda Myōjin. This, like Michizane, is the textbook goryō belief of enshrining a raging vengeful spirit and turning it into a protecting god. The ups and downs—drawing the reverence of the people as the great tutelary of Edo, being removed from the enshrined deities as a traitor in the Meiji era, and being restored at the end of Shōwa—also reflect well the duality of the image of Masakado as a hero who rebelled against the throne. In later ages, the story of his daughter Princess Takiyasha commanding a giant skeleton won popularity in kabuki and popular fiction and was depicted in Utagawa Kuniyoshi's "The Old Palace at Sōma"; it should be noted that this is a derivative starring the daughter, not Masakado himself.

A framework that enshrines vengeful spirits as goryo to pacify their curses and turn them into sources of blessing. Epidemics and natural disasters were seen as manifestations of resentment, and reconciliation was sought through founding shrines, conferring divinity, and institutionalizing festivals. Curse deities bear a dual aspect of fear and veneration, and their wild power was believed to transform into communal guardianship through proper requiem rites. Practices ranged from state rituals to village memorials, including era name changes, imperial envoys, Goryo-e, and Hojō-e. For individuals, memorial offerings, sutra copying, nenbutsu, and esoteric prayers were performed, while restoring honor and granting divine ranks were means to ease a spirit’s grievances. Narratives and origin legends explained why resentment arose, giving social memory to causes such as false accusation, untimely death, and broken lineages. A vengeful spirit’s power was not indiscriminate but signaled its intent according to causes, believed to speak through dreams, oracles, thunder and fire, and plague. Pacification was not a one-time act but continued through annual festivals and shrine upkeep, with warnings that neglect would invite resurgence.