[1] After the rebellion of Fujiwara no Hirotsugu in 740, Emperor Shōmu relocated his seat to Kuni-kyō (恭仁京) (currently part of Kizugawa, Kyoto) and also built a detached villa deep in the mountains of southern Ōmi, which was called "Rakumura".

[2] On the other hand, Emperor Shōmu may have been influenced by Buddhist prelates such as Rōben and Gyōki, who saw the area as a holy site.

An indication of this is the plans Emperor Shōmu announced the following year for the construction of a monumental image of the Vairocana Buddha in emulation of the Longmen Grottoes in Tang dynasty China near the Shigaraki site.

[3] In 744, the name of the palace gradually changed from "Shigaraki" to "Kōka", and in November of the same year, the central support pillar of the Vairocana Buddha statue was erected at Kōka-ji, a Buddhist temple which had been established to house the image.

However, the vast expense required for the project resulted in resistance by many of his vassals, and a series of natural disasters such as wildfires and the Tenpei Earthquake forced Emperor Shōmu to return to Heijō-kyō.