At the heart of the lore surrounding Michizane's curse lies the lightning strike on the Seiryōden in the eighth year of Enchō (930). In the Seiryōden, where Emperor Daigo presided over a council called to pray for rain amid drought, black clouds welled up from the direction of Atago and lightning fell: Major Counselor Fujiwara no Kiyotsura, said to have kept watch over Michizane at Dazaifu, took fire to his robes and was struck dead with his chest torn open, while the Middle Controller of the Right Taira no Mareyo had his face burned and lost his life [1]. Emperor Daigo, having witnessed the carnage, fell ill and passed away within three months. This single event made the belief in Michizane as a thunder god unshakable. The sight of Michizane transformed into a thunder deity, descending upon the capital to strike the Seiryōden, is vividly depicted in the Kamakura-period Kitano Tenjin Engi Emaki^[2], and casts its shadow over later paintings of the wind and thunder gods.

At Dazaifu, by contrast, a gentler tradition survives. As Michizane's remains were being borne by ox-cart to burial, the ox sat down before a gate and would not move; that place was chosen as the grave and a shrine was built—this is held to be the origin of Dazaifu Tenmangū. The many images of reclining oxen (sacred oxen, "stroking oxen") in the precincts of Tenjin shrines derive from this story. At Kitano in Kyoto, in the fifth year of Tengyō (942), a young girl of the western capital named Tajihi no Ayako received an oracle to "enshrine me at Kitano," and a shrine hall was raised later, in the first year of Tenryaku (947). Kitano had originally been a land of the thunder god where lightning was frequent, and upon the soil of a belief that to revere a raging thunder god is to turn him into a god who brings rich harvests, Tenjin was at last quieted.

The plum lore is equally famous. As Michizane prepared to leave the capital, he addressed a poem to the plum tree of his residence—"When the east wind blows, send forth your fragrance, blossoms of the plum; though your master be gone, do not forget the spring"—and the plum, longing for its master, is said to have flown in a single night all the way to Dazaifu. This is the sacred tree of Dazaifu Tenmangū, the "Flying Plum" (Tobiume). It should be noted that in its oldest sources, the Shūi Wakashū^[3] and the Ōkagami^[4], the closing line reads "do not forget the spring" (haru o wasuruna), differing in form from the later-popular "do not, spring, be forgotten" (haru na wasure so).

Michizane is counted, together with Taira no Masakado and Emperor Sutoku, among the "Three Great Vengeful Spirits of Japan." Yet this grouping of the three is not an old classification; the integration of Yamada Yūji and others^[5] in the study of vengeful spirits has shown it to be an early-modern framework that spread through the popular fiction and kabuki of the Edo period. A man of letters who wept under a false charge, became a thunder god who shook the throne, and came at last to be revered as the god of learning—Michizane's story has been handed down for over a thousand years as the very archetype of goryō (vengeful-spirit) belief.