Why did counting rods fall out of use in China?

In China, counting rods were a foundational tool used on a counting board to perform calculations using a decimal place-value system. Their decline as a primary mathematical instrument was closely linked to the rise of the abacus, known in China as the suan pan.12

By the 17th century, counting rods had largely fallen out of use as a counting tool. This shift occurred alongside the rapid diffusion of the abacus, which became the preferred instrument for arithmetic, supported by the publication of influential texts such as Cheng Dawei’s Suanfa tongzong (1592).2

The abandonment of rods had significant consequences for Chinese mathematics. Because the sophisticated algebraic place-value notations of the Song-Yuan period were physically based on the manipulation of these rods, the loss of the instrument made those ancient methods difficult to understand. Consequently, by the 17th century, advanced techniques like the "method of the celestial unknown" had been largely forgotten until they were later deciphered by scholars using Western algebra.2