Before the Kansei-reki (Kansei calendar) was introduced, ' Heikiho' (a way of expressing 24 divisions of the old calendar) was used and was calculated by dividing one year equally (divided by time), into 24 divisions of the old calendar.
寛政暦までは、二十四節気を1年間を等分（時間分割）して計算する「平気法」が使用されていた。