Also, divided prevailing price in the cities into three ranks as upper, middle, lower (each was described as three ranks further such as expensive or cheep, so it was actually nine ranks) every 10 days (once a month in the 'Engishiki' [an ancient book for codes and procedures on national rites and prayers]).
また、10日ごとに（「延喜式」では毎月1度）市における時価を上中下の3等に分けた（その中でも更に高値安値などの3段階表記をしたため、実質は9等）。