1 ri represented the area of 1800 shaku (unit of length, approximately 30.3 centimeters) square (1800 shaku is equivalent to 360 bu [unit of length in old Japanese system of weights and measures] or 6 cho [unit of length, approximately 109 meters]).
1里は1800尺（360歩(尺貫法)、6町(単位)）四方の面積を表していた。