The time when humans started to require measurement coincides with the dawn of ancient civilization.
We hear that the unit "yard" was created from the length of an arm, and "inches" and "feet" from the thickness of a finger. "Seconds" came from heartbeats, "minutes" from the movement of the sun, and "days" from the waxing and waning of the moon.

In Japan, the Taiho Code (Taiho Ritsuryo) was established in the year 701. "Shaku-do (scale)" and "To-ryo (measuring)" were adopted. The nationwide measuring of agricultural fields "taiko-kenchi" was conducted by Hideyoshi Toyotomi in 1590 (Tensho 18).

In the Edo period, the land (magnitude) of a daimyo (feudal load) and the stipend (salary) of a samurai was expressed in "goku-daka" established after taiko-kenchi.
* 1 koku = 10 to = 1000 gou 1 koku = 180 liters = 150kg (1 koku was based on the quantity of rice a person ate in a year)

Until the early years of Showa, the shaku scale was used as a measuring standard for textiles, "Issho masu" or "Ichigo masu" volume measures for rice, liquor and soy sauce, and the "tenbin (balance)" for weight trading.

In the year 1786, Gennai Hiraga invented the thermometer. It was in 1814 (Bunka 4) when Tadataka Ino completed an astonishingly precise map by pacing out the distance and measurement of the meridian line across Japan.

Even today, the customs of using "tsubo" for the area of lands and buildings and "tan" for the area of agricultural land widely remain.
* 1 tsubo = 3.3m², 1 tan = 300 tsubo (Area of land that can grow 1 koku of rice)
* 1 rice bale = 4 to = Approximately 60kg
* 1 ken = 1.818m (There are still many architectural parts made in the unit ken for housing column spaces, window sashes, door widths, etc.)

Japan joined the Meter Convention in 1886(Meiji19 ), and this date was defined as Meter Day.

The Weights and Measures Act was issued in 1891 (Meiji 24), and the units were changed to "shaku" for dimensions and "kan" for weights. The Weights and Measures Act was issued in 1921 (Taisho 10) for unifying to the metric system, and this date was defined as Metrology Day. The units were unified to “meters” for dimensions, and to “kilograms” for weights.

On November 1, 1993 (Heisei 5), the Measurement Law was amended, and this day was defined as Metrology Day.
The measuring units were unified to the International System of Units (SI unit), and the traceability system was established.

The symbol of equality and fairness

For your reference, the badge of a lawyer bears an image of a “balance” as a symbol of "Equality and Fairness".

The family of scales

Today, many scales are used around us, such as for the foods sold for a price in a shop, commodities with a label indicating weight and price, and gas meters. The meters for water, town gas, electric power, dimensions and weight, as well as the clinical thermometers, sphygmomanometers, etc., required for healthcare, are all in the family of "scales."