suanpan

The suanpan, also known as the Chinese abacus, is a traditional calculating device used for arithmetic in China and parts of East Asia. It consists of a rectangular frame with a series of rods, each rod corresponding to a decimal place. Beads slide on the rods, with two beads on the upper deck and five beads on the lower deck. Each upper bead weighs five units; each lower bead weighs one unit. Beads are moved toward a central bar to represent numbers; the total on a rod represents a digit from 0 to 9 for that place. To perform calculations, users manipulate beads across rods to carry and borrow as needed.

Design and use: Typical suanpans have 13 to 15 rods, and are built of wood, bamboo or plastic; the frame is oriented so that digits move away or toward a central beam. The upper deck beads count as 5s, the lower deck beads count as 1s. Calculations are performed by sliding beads and carrying tens between rods.

History: The suanpan has ancient origins in China and was the dominant tool for arithmetic in commerce and education for many centuries. It significantly influenced the development of later abaci in East Asia, including the Japanese soroban, which uses a similar structure but with one bead on the upper deck and four on the lower deck.

Modern use: Although calculators and digital devices have supplanted its routine use, the suanpan remains an iconic symbol of traditional calculation. It is still taught in some schools and used by merchants and hobbyists, and it is employed in demonstrations of arithmetic techniques and mental calculation training.