Scene from Kitano tenjin engi (The Origins of the Kitano Deity) illustrated scroll (13th c.)

In this scene, Michizane purifies his body for seven days and writes a prayer to the gods (both Buddhist and Shinto) asking their permission to wreak vengeance on his enemies. Then he climbs to the top of Mt. Tempai. He ties the prayer to a long pole, and stands on his tiptoes for seven days. At the end of seven days, a black cloud comes down from the skies and takes the petition up to the distant heavens, indicating that his petition has been granted.

For more on how illustrated scrolls about Tenman Tenjin were used in the Kamakura period, see Borgen pp. 325-327.