In "Seiji Yoryaku (Brief Outline of Government)," a book written in the Heian Period, it is recorded that the first calendar made by the Japanese people was distributed on the first day of January in 604, and it is believed that the said calendar was based on Genkareki.
平安時代の書物『政事要略』には、推古天皇十二年正月朔日に初めて日本人の手によって作られた暦の頒布を行ったとの記述があり、これは元嘉暦によるものであったと考えられる。