How to Use a Soroban: A Step-by-Step Guide for Beginners

The soroban is the Japanese abacus and the core tool of mental arithmetic. This guide walks step by step through the parts of the soroban, setting numbers, finger technique and the first addition and subtraction examples. If you are new to the method, you may want to start with our article on what mental arithmetic is.

Parts of the soroban: frame, beam, rods and beads

Place the soroban on the table with its long side facing the child. It has:

• Frame — the outer part that holds everything together.
• Beam (reckoning bar) — the horizontal bar that splits the soroban into an upper and a lower deck. All counting happens relative to it.
• Rods — the vertical sticks the beads slide on. Each rod is one place value: from right to left, ones, tens, hundreds, thousands and so on.
• Upper bead — one per rod, worth 5.
• Lower beads — four per rod, each worth 1.
• Unit dots — small marks on the beam, usually on every third rod. They help you pick the ones rod and read large numbers in groups of three.

There is one key rule: a bead counts only when it touches the beam. A bead pushed away from the beam is worth zero.

Starting position: clearing the soroban

Before every problem the soroban is set to zero. Tilt it slightly towards yourself so the lower beads drop down. Then lay it flat and run your index finger along the beam from left to right, pushing the upper beads up. Now no bead touches the beam — the soroban is clear. Make this movement automatic: it happens before every single problem.

Setting the numbers 0 to 9

Any digit can be shown on a single rod:

• 0 — no beads touch the beam.
• 1, 2, 3, 4 — push that many lower beads up to the beam.
• 5 — bring only the upper bead down.
• 6, 7, 8, 9 — the upper bead (5) plus 1, 2, 3 or 4 lower beads.

For example, to set 7, bring the upper bead down and push two lower beads up: 5 + 2 = 7.

Two- and three-digit numbers

First choose the ones rod — usually one of the rods with a unit dot. The rod to its left is tens, the next one hundreds. To set 46: four lower beads on the tens rod; on the ones rod, the upper bead and one lower bead. To set 305: three lower beads on the hundreds rod, the tens rod stays empty (that is the zero), and only the upper bead on the ones rod. Not "losing" the empty rod is one of the most important beginner skills.

Finger technique: which finger does what

Only two fingers work the soroban — the thumb and the index finger:

• The thumb pushes lower beads up to the beam.
• The index finger does everything else: brings lower beads down, brings the upper bead down to the beam and pushes it back up.

It feels awkward at first, but this split is exactly what makes the movements fast and accurate. Several beads can move in one motion: to set 9, the index finger brings the upper bead down while the thumb pushes four lower beads up at the same time. Teach your child not to rush — correct movement first, speed later.

First addition and subtraction (without "friends")

The first problems are chosen so the beads you need are free on the rod. On the soroban you work from left to right — from the highest place value to the lowest.

Example: 3 + 5. Set 3 (three lower beads up). To add 5, bring the upper bead down with your index finger. Result: 5 + 3 = 8.

Example: 26 + 12. Set 26: two lower beads on the tens rod; the upper bead and one lower bead on the ones rod. First add 1 to the tens — push up one more lower bead (3). Then add 2 to the ones — push up two lower beads (5 + 3 = 8). Answer: 38.

Example: 87 − 25. The tens rod shows 8 (upper + 3 lower): to take away 2, bring two lower beads down, leaving 6. The ones rod shows 7 (upper + 2 lower): to take away 5, push the upper bead back up, leaving 2. Answer: 62.

When the "friends" rules come in

Now try 4 + 3. All four lower beads are already up — there is no room to add 3 more. This is where the formulas start. If you cannot add 3 directly, add 5 and remove the extra 2: +3 = +5 − 2. The result is 7. This is the small friends rule — pairs that add up to 5 (1-4, 2-3).

When a rod is full, as in 7 + 8, you have to move to the next rod: +8 = +10 − 2. Add one bead on the tens rod, take 2 from the ones, and you get 15. This is the big friends rule — pairs that add up to 10. Later come mixed formulas where both rules work together. The key point: move on to formulas only once your child sets numbers and adds directly with confidence.

Common beginner mistakes

• Not clearing the soroban before a problem — a bead left over from the last problem ruins the answer.
• Not fixing the ones rod — the number gets shifted and 46 turns into 460.
• Leaving a bead halfway — a bead that does not fully touch the beam is easy to misread.
• Using one finger for everything — speed does not grow and movements get messy.
• Counting on fingers first, then setting the beads — the whole point of the soroban is to get away from counting one by one. See our article on moving beyond finger counting.

How to practise on MentalMath

Even without a physical soroban at home, you can start with three trainers on the site:

1. Soroban reading game — reading and setting digits 0–9 on a single rod. On the easy level the child reads the digit shown; on the hard level they set the given digit themselves.
2. Virtual Soroban — you type a problem (for example 26+12), choose a method (direct, small friends, big friends and others), and the program shows every bead movement step by step. Set the speed to slow and talk through the steps together.
3. Solve on the Soroban — the child gets a problem, moves the beads to build the answer and checks it. Easy level: adding two-digit numbers; medium: three-digit addition and subtraction; hard: four-digit numbers.

Ten to fifteen minutes a day is enough: first read and set a few numbers, then do 5–10 problems. If you are unsure whether your child is the right age, read our article on what age to start the abacus, and to find out where to begin, take the placement test — practice will start at your child's level.