Soroban (Japanese abacus)
Soroban ? Késako ?
The soroban more commonly known as the “Japanese abacus” is made up of an odd number of columns or rods, each with beads: a separate bead with a value of five, called go-dama (五玉, ごだま, “quinary bead”) and four beads each with a value of one, called ichi-dama (一玉, いちだま, “unary bead”). Each set of pearls in each row is divided by a bar called a count bar. The number and size of the beads in each rod make a standard-size 13-rod soroban much less cumbersome than a standard-size Chinese abacus (or suanpan) of similar expressive power.
The number of rows in a soroban is always odd and never less than seven. The most common models generally feature thirteen rods, but the number of rows on practical or standard models is often increased to 17, 21 or even 27, allowing more digits to be calculated or several different numbers to be represented at the same time. Each row represents a digit, and a larger number of rods allows more digits to be represented, either in singular form or during operations.
Why a soroban?
We’re often asked: why learn soroban? What are the benefits?
Learning Soroban has many benefits for children:
- Helps develop the qualities of concentration and patience.
- Helps develop an intuitive understanding of numbers thanks to their concrete representation on the soroban.
- Develops the child’s ability to memorize
- Demonstrates the concept of decimals and the progression from units to tens physically: order of magnitude is represented intuitively.
- Performs addition and subtraction operations instantly when numbers are placed on the abacus.
- Promotes confidence in the calculation process by allowing observation in action.
- Allows children to break down operations.
- Uses a left-to-right calculation method, enabling rapid estimation and rounding.
- Works on the decimal rather than fractional system, an easy progression to numerical systems.
- Develops mental arithmetic, an extremely valuable skill.
- Develops the right brain.
- Expresses large numbers simply and easily.
- Gives a sense of achievement as skills improve.
- Helps develop the child’s fine motor skills.
The soroban is a powerful arithmetic instrument, but it makes the most sense as an educational tool for learning mathematics at school.
Soroban is particularly suitable for primary school children, from CP to CM2.
CE1 and CE2 are undoubtedly the best time to introduce soroban.
Unlike the calculating machine, the soroban requires the child to think: it gives an intuitive understanding of calculation operations, and helps memorize addition and multiplication tables. Performing a calculation requires a breakdown of the operation, which helps the child to better assimilate arithmetical concepts.
After using the soroban for a while, the child will be able to perform mental calculations of a higher order of magnitude almost innately. After a while, the operating techniques of the abacus can be applied to mental arithmetic: this is called Anzan :
- children who have fully mastered the soroban can ignore it and perform complex calculations in their heads, without the need for a calculator.
Most mathematical operations are possible with the soroban, including addition, subtraction and even multiplication and division (if you’re familiar with the multiplication table). However, to carry out arithmetic operations involving multiplication and division, you’ll need a large soroban (with at least 13 columns), especially if you’re using decimal numbers!
The soroban is acclaimed by many mathematicians for its educational role in teaching elementary arithmetic. The soroban lets you play mathematical games, turning learning into a game. The soroban is now increasingly popular for teaching mathematics in elementary school. The soroban is a powerful didactic tool that has proven its effectiveness in many educational systems with millions of young children learning arithmetic.
The basic operations (adding and subtracting) are very simple to learn, and in just a few minutes your child will know how soroban notation works and how to use it to make calculations. Adding is very easy indeed, and from the result of the addition the process is simply reversed to subtract.
Multiplying requires a slightly different logic, but is still very easy and quickly becomes a calculating game for the child.
Soroban history
A unique feature that distinguishes the Soroban from its Chinese cousin is the absence of 2 beads: only 1 quinary counter (as opposed to 2) and 4 unit counters (as opposed to 5).
The number of beads is identical to that of the Roman abacus, which had four beads at the bottom and one at the top.
Most historians agree that its roots go back to the importation of the Chinese abacus to Japan via the Korean peninsula around the 14th century, when the suanpan arrived in Japan under the name of soroban (with its beads modified to make it easier to use), it had two celestial beads and five terrestrial beads. But soroban was not widely used until the 17th century, although it had been used by Japanese merchants since its introduction.
By the time the soroban itself was built, the number of beads had begun to diminish. Around 1850, a celestial bead was removed from the suanpan configuration of two celestial and five terrestrial beads. This new Japanese configuration existed alongside suanpan until the beginning of the Meiji era, after which suanpan fell completely out of use in Japan. In 1891, Irie Garyū removed yet another single ball, forming the modern configuration of one celestial ball and four earth balls. This configuration was then reintroduced in 1930 and became popular in the 1940s.