Gihō calendar

, also known as "Yi-feng li" or "Rentoku-reki", was a Japanese lunisolar calendar ("genka reki").
History.
The calendar was created in China. It was first used in the "Rintoku" era during the Tang Dynasty..
The "Gihō-reki" system was brought from Korea to Japan in "Yi-feng" era (676-678) of the reign of Emperor Gaozong of Tang. This calendar corrected errors in the "Yuan-jia li" (Genka calendar) which was developed in China. For a short time, both "Genka" and "Gihō" calendars were in use.