When was the watch invented? Who invented the watch?

Gauge is an astronomical instrument for measuring the length of sun shadow, which consists of gauge and gauge. As early as the 20th century BC, the standard gauge method was used in the Central Plains of China. By the 7th century BC, our ancestors had invented the standard gauge.

Scholars in the Han Dynasty also determined the "twenty-four solar terms" by using the length of the sun shadow, determined the shortest day in the Yellow River basin as the winter solstice, took the winter solstice as the starting point of the "twenty-four solar terms", and divided the period from winter solstice to winter solstice of the following year into 24 segments, each of which was 15 days.

The standard table can be used not only to formulate festivals, but also to list the future solar calendar year and the dates of 24 festivals in the almanac as an important basis for guiding the agricultural activities of the working people of the Han nationality.