Then it came to be called "kokorotei", and by further extension, "tokoroten"; however, it seems that names such as "kokoroten" and "tokoroten" were already used in the Nara period as is shown by its mention in days gone by in a writing stored in Shoso-in Treasure Repository.
それがこころていと呼ばれるようになり、さらに転じてところてんとなったとされるが、古くは正倉院の書物中に心天と記されている事から奈良時代には既にこころてんまたはところてんと呼ばれていた様である。