The name of the castle first appeared in the authentic history in the article of the renovation during the era of Emperor Monmu (in 698), however, the document has no description about the year when it was constructed and even now it remains unknown.
文武天皇時代の修築記事（698年）ではじめてその名が正史に登場するが、築城年は記載がなく現在も確定されていない。