Zhu Zaiyu’s greatest contribution to ancient culture was his creation of the twelve equal laws. This theory is widely used in keyboard instruments around the world, including pianos, so Zhu Zaiyu is known as the "originator of piano theory." Written by Zhu Zaiyu

Zhu Zaiyu used a very large abacus spanning 81 levels to perform square root and cube root calculations, and proposed the "reducer theory". Based on this, he designed and Produce strings and tempered pipes. Zhu Zaiyu's "Twelve Equal Temperament" makes the increase or decrease of the temperament of each adjacent two keys of these twelve keys equal. After decades of painstaking research, Zhu Zaiyu finally solved this academic problem in the field of music for more than a thousand years with his theory of twelve equal temperaments. Once the twelve equal temperament appeared, eighty-nine out of ten musical instruments in the world were based on the twelve equal temperament's pronunciation and theoretical standards. For example, the piano, known as the "King of Musical Instruments", was invented based on the principle of twelve equal temperaments. Perhaps this kind of professional vocabulary in music is confusing for us, so let us quantify it: to this day, the tuning of nine out of ten musical instruments in the world is completed on the basis of twelve equal temperaments. It is used by today’s Westerners It is generally considered to be "standard tuning" and "standard Western temperament".