Taishokan is a story loosely based on the life of Fujiwara no Kamatari (614−69), who was a famous court official. In the story, the daughter of Kamatari is married to the emperor of China. When she hears that her father is going to build the main hall of the Kōfuku-ji Temple in Nara, she sends him Mugehōju, a precious crystal with divine powers, as a gift. While a military escort is sailing to Japan with the crystal, dragons attack the ship and the treasure is carried down to the palace of the dragon king at the bottom of the sea. To get the gem back, Kamatari devises a clever plan: he lures the dragon king up to the surface with dazzling music and dance, at the same time sending his concubine, who is an ama (woman diver), to sneak into the dragon's palace and retrieve the crystal. Books of this kind, with hand-drawn, full-color illustrations, are called nara-ehon, and were produced in the 17th century. The front cover shows a huge tree full of cherry blossoms, lavishly painted in gold against a deep-blue background.