What is a soroban? (and how it differs from the Chinese abacus)

New to the soroban? Start with the basics.

A soroban is the Japanese abacus: one bead worth 5 above the bar and four beads worth 1 below it on each rod, usually 23 rods. The Chinese suanpan has two 5-beads and five 1-beads per rod. The soroban's smaller layout is what makes "anzan", calculating on an imagined abacus, possible: fewer beads means a simpler picture to hold in the mind.

The parts

A digit is shown by pushing beads toward the beam: 7 is the upper bead down plus two lower beads up. Numbers up to 9 fit on each rod, so a 23-rod soroban shows a 23-digit number.

Soroban vs Chinese abacus (suanpan)

The abacus reached Japan from China around the 16th century. The one-upper-bead form spread in Japan during the 19th century and became standard in the 1930s, when Japanese schools adopted the 1/4 layout.

What children learn on it

Japanese schools teach the soroban briefly in grades 3 and 4. Abacus schools go much further. A child typically learns, in this order:

1. Placing and reading numbers (a few weeks)
2. Adding and subtracting without complements
3. 5-complements: to add 3 when only two 1-beads are free, add the 5-bead and remove 2
4. 10-complements: carrying and borrowing across rods
5. Multi-digit addition and subtraction (mitori-zan), the core of every exam
6. Multiplication, then division (from roughly the 9th and 7th kyu in Japanese grading)
7. Anzan: doing all of the above on an imagined soroban, with no physical beads

The last step is the reason most parents choose the soroban over other arithmetic methods. Brain-imaging studies show that expert abacus users calculate with the visuospatial areas of the brain rather than the language areas, which is why they can add ten 3-digit numbers in their head without "saying" any of it.

Why the layout matters for learning

Every operation on a soroban reduces to a small set of bead movements. That has two consequences. Errors are specific and diagnosable: a wrong answer is almost always a missed 5-complement, a missed carry, a shifted column or a copying slip. And practice is short: ten minutes a day on the right level moves a child faster than an hour once a week. Good soroban tools, whether a teacher, a workbook or an app such as Soroban Kingdom, are built around those two facts: fine-grained levels and visible mistakes.

The conditions of good soroban learning are the same wherever it happens: fine steps, visible mistakes, daily short practice, and a level system that leads to a real exam.

Frequently asked questions

Is "abacus" the same as "soroban"?

Abacus is the general word. Soroban is specifically the Japanese one-upper-bead abacus. Most "abacus mental math" programs for children outside Japan (UCMAS, ALOHA and others) use the soroban layout, not the Chinese one.

Do you need a physical soroban to learn?

Yes for the first year. The mental picture used in anzan is built from the memory of moving real beads. On-screen sorobans are fine for daily practice, but children should still move a real one regularly. A 23-rod student soroban costs about $15–30.

Which size should a child buy?

23 rods. It fits every exam format up to the highest levels, and it is what abacus schools use. 13-rod pocket models are too short for multi-digit multiplication.