Seiryoden Thunderbolt Striking Incident (清涼殿落雷事件)

The Seiryoden thunderbolt striking incident happened when a thunderbolt struck the Seiryoden (literally, Hall of Cool and Refreshing Breezes; the emperor's private residence) in the Dairi (Imperial Palace) on July 29, 930 during the Heian period.

Since Heiankyo and its environs suffered drought that year, the conference of Daijokan was to be held in the Seiryoden, Emperor Daigo's living quarters, on July 29 to discuss whether or not to hold a praying-for-rain ceremony. Ironically, however, around one o'clock in the afternoon on that day, dark clouds lowered on Mt. Atago (Kyoto City) and overwhelmed Heiankyo along with a thunderstorm -- About an hour and a half later, a thunderbolt struck the first pillar at the southwest corner of the Seiryoden.

The court nobles and government officials at the scene were injured: among the court nobles, Dainagon (Major Counselor), Minbukyo (Minister of Popular Affairs) FUJIWARA no Kiyotsura's robe caught fire, his chest was burnt and he died instantly, and Uchuben (Middle Controller of the Right) Kura no kami, (Chief of Kuraryo, Bureau of Palace Storehouses) TAIRA no Mareyo, suffered burns on his face, which was a serious injury. Secretly, Kiyotsura's body was carried from the Palace through the Yomei-mon Gate on a vehicle, and Mareyo was through the Shumei-mon Gate on a vehicle, but he died soon afterwards. Lightning flashed through the Shishinden (hall for state ceremonies), and Uhyoe no suke (assistant captain of the Right Division of Middle Palace Guards) MINU no Tadakane's hair caught fire and he died, Uhyoe no suke KI no Kagetsura's stomach was burnt and he died, Azumi Munehito's knees were burnt and he died, and two guards of Konoefu (the Headquarters of the Inner Palace Guards) died.

The court nobles who were in the Seiryoden and were able to escape danger were thrown into a panic, and Emperor Daigo escaped hurriedly from the Seiryoden to the Joneiden (Empress' residence). Yet, having witnessed such a horrible sight, the Emperor fell into poor condition and died three months later.

From the shocking fact that the thunderbolt struck the Emperor's residence, and the fact that the dead SUGAWARA no Kiyotsura had once spied on SUGAWARA no Michizane's movements under orders of FUJIWARA no Tokihira when Michizane was exiled to Dazaifu, a rumor spread that Kiyotsura was killed by the vengeful spirit of Michizane. It was further believed that the vengeful spirit of Michizane manipulated the thunder, which originated the prevalent legend of Michizane that he became the god of thunder.