Suanpan & Soroban Abacus: History, Use, How-To Guide

Introduction

Abacuses are commonly seen in ancient civilizations around the world as a convenient tool for simple calculations. In this article we focus on the traditional Chinese and Japanese abacuses—suanpans (China) and sorobans (Japan)—their history, design differences, and how to read and use them.

Abacus Etymology

The Chinese word 「算盤」, pronounced “suanpan,” literally means “calculating tray” or “calculating disk.” In Chinese it is sometimes used metaphorically to mean planning or calculating matters.

The Japanese word 「そろばん」, pronounced “soroban,” is a borrowing and adaptation of the Chinese term.

Suanpans in China

Origins

Prototypes of the suanpan began appearing during the Han dynasty (206 BC–220 AD). Early designs resembled modern suanpans, with one bead above and four beads below the beam. Scholars believe the design was influenced by devices such as the Roman hand abacus, exchanged through trade and cultural contact.

The Roman hand abacus was a calculating tray with grooved slots and sliding metal ball bearings. The suanpan innovation was to use beads on rods, which were cheaper and easier to manufacture in bamboo.

Evidence in Art

Visual evidence of suanpan use appears in the famous Song Dynasty painting “Along the River During the Qingming Festival.” It is likely the suanpan shown in the painting was used to calculate prices for goods such as Chinese medicine powders.

Design changes

The suanpan design changed in the Ming and Qing dynasties (1368–1912) to a 2:5 bead configuration (two beads above and five below the beam). That 2:5 layout reflected the hexadecimal weight units used in some calculations at the time and is the version many Westerners now recognize as the suanpan.

Sorobans in Japan

During Japan’s Muromachi period (around the 14th century), the 2:5 suanpan design arrived from Ming China through trade. Japanese users considered the 2:5 layout unnecessarily complex and simplified it to a 1:4 bead design (one bead above, four below), which matched earlier Chinese designs. The simplified Japanese version is called the soroban.

Modern Suanpans and Sorobans

Suanpans largely faded from everyday use in China after the adoption of metric units and the rise of electronic calculators. Today they are mostly found in museums and antique shops.

Sorobans, however, remain in common use in several Asian regions because their 1:4 decimal layout maps directly to base-10 arithmetic. Many elementary schools in Japan, Taiwan, and parts of China include soroban training or clubs.

Modern sorobans typically use a 23-column design for decimal calculations and are sold in wood or plastic. Some manufacturers add a clearing mechanism for convenience.

Appearance and Features

A modern 23-column soroban can represent large numbers and even handle two distinct calculations simultaneously by using different column groups.

The small dots on some sorobans act like thousands or decimal separators on a numeric display (for example, the commas in 1,000,000).

Some sorobans include a clearing button at the top that zeros all columns instantly:

How to Express Numbers on a Soroban

Sorobans use a bi-quinary (two-base-5) encoding to represent each decimal digit. Each column stores one decimal digit using one upper bead (value 5) and four lower beads (each value 1).

Read numbers left to right across columns. For example:

Clearing the Soroban

If your soroban has a clearing button, press it to reset all beads. If it doesn’t, clear by hand: place your thumb and index finger on the beam and sweep across to move all beads to their cleared positions.

Other Cool Facts

• Suanpans (the 2:5 bead design) have been used to play checkers—see the abacus checkers page for rules and history.
• In 1947, a soroban was entered into a calculation contest against an electronic calculator in Japan; the soroban won four out of five rounds, losing one multiplication round.
• Beyond basic arithmetic, sorobans can be used to compute square roots, cube roots, and higher-degree roots (often using algorithms such as Newton’s method).

Advanced operations and references

1. Square roots: Square root on the abacus
2. Cube roots: Cube root method (PDF)
3. Higher-degree roots (Newton’s method): Math StackExchange discussion

Final Thoughts

Suanpans and sorobans have been primary accounting tools for centuries and remain in active use in many Asian countries. Learning to use a soroban can be an engaging way to improve arithmetic skills and teach children about numbers—while also reducing reliance on battery-powered calculators.

Further Resources

• Online soroban/suanpan emulator: Marburg University abacus demo
• Addition on soroban: Arithmetic on the abacus (addition)
• Multiplication on soroban: Using the abacus (multiplication)
• Division on soroban: Division on the abacus — division can also be done digit-by-digit, which many find faster.
• News article on the soroban vs. calculator contest: Wired: Abacus beats calculator
• General abacus history and resources: Abacus history and Abacus index