Every bead frame compared: how many beads, and what each one is for
A soroban rod holds five beads, a suanpan rod holds seven, a schoty wire holds ten and a rekenrek has twenty beads that are all worth one. One table, one section per frame, and the two errors that circulate about them corrected.
How many beads does an abacus have? The question has no single answer, because the word covers at least four living instruments that count in genuinely different ways. A Japanese soroban rod holds five beads. A Chinese suanpan rod holds seven. A Russian schoty wire holds ten and has no dividing beam at all. A Dutch rekenrek holds twenty beads in total, and not one of them is worth more than one. This page is a reference: a table first, then a short section per frame, so you can tell which instrument is in the photo you are looking at and what it was actually built to do.
| Frame | Beads per rod | Decks | What one bead is worth | Mainly used for |
|---|---|---|---|---|
| Soroban (Japan) | Five — one above the beam, four below | Two, split by a reckoning beam | Five above the beam, one below | Mental-calculation training and the Japanese graded exams |
| Suanpan (China) | Seven — two above the beam, five below | Two, split by a reckoning beam | Five above the beam, one below | Decimal arithmetic with carry room, and traditional non-decimal units |
| Schoty (Russia) | Ten on most wires, four on at least one short wire | One slanted deck, no beam | One, on every wire | Everyday and accounting arithmetic in Russian offices and schools |
| Rekenrek (Netherlands) | Ten per row, twenty in total | One frame, two rows | One, on either row | Early number sense — counting, with five and ten as anchors |
The 1:4 soroban: five beads a rod, and why one of them is worth five
A modern soroban rod carries one bead above the reckoning beam and four below it. The bead above — the go-dama, or heaven bead — is worth five. Each of the four below, the ichi-dama or earth beads, is worth one. Push beads towards the beam to count them, and a single rod encodes every digit from 0 to 9 in exactly one way: seven is the heaven bead down plus two earth beads up, and there is no second arrangement for it. Two things get garbled about this constantly, so here they are straight. The go-dama is a value-five bead, not a decimal-point marker. And the decimal position is not printed on the frame at all — you decide which rod is the units rod, and every other place value follows from that choice.
The 1:4 layout is also younger than most people assume. Reference accounts of the soroban describe a frame that once carried more beads: one heaven bead dropped from the design around 1850, Irie Garyu removing an earth bead in 1891, a reintroduction in 1930, and the 1:4 frame only becoming the common one through the 1940s. Those dates rest on a short reference lineage rather than a deep scholarly literature, so treat them as the received account rather than as settled history.
The 2:5 suanpan: seven beads a rod, and what the extra two buy
A suanpan rod carries two beads above the beam and five below — seven beads against the soroban’s five. The instrument is bigger too: roughly 20 cm tall, and usually with more than seven rods. The extra beads are not decoration. Because a rod can hold a value above nine, a practised user can park an intermediate result on a rod instead of carrying immediately, and that is real working room in long multiplication and division. This is also the tradition with formal cultural recognition: Chinese Zhusuan, knowledge and practices of mathematical calculation through the abacus, was inscribed on UNESCO’s Representative List of the Intangible Cultural Heritage of Humanity on 4 December 2013, at the Committee’s eighth session in Baku.
Now the correction, because this one is everywhere: the suanpan is not a base-16 device. Both frames are decimal. What is true is that traditional Chinese weight arithmetic was not purely decimal — one jin was divided into sixteen liang — and a rod that can count past fifteen suits that kind of conversion work very comfortably. That is a use case, not a number base. When a page tells you the suanpan runs on base 16 and that the soroban’s top bead marks the decimal point, it has repeated two separate mix-ups in one breath.
The Russian schoty: ten beads a wire, one deck, no beam
The schoty looks unrelated to the East Asian frames, and structurally it is. It has a single slanted deck, ten beads on most wires and no dividing beam, so every bead on a wire sits in the same row and each one is worth one; the middle two beads of a wire are usually a different colour, so the eye can find five without counting. At least one short wire carries four beads instead of ten, for fractions of the currency unit — sources differ on whether those quarters were of the ruble or of the kopek, so the honest statement is just that the wire existed for sub-unit fractions. Nor is it only a museum object: the schoty was still taught in most Russian schools until the 1990s, and began losing ground only after domestic microcalculators went into mass production in 1974. Writing in Accounting History in 2023, Sokolov, Karelskaia and Zuga describe it as a unique Russian counting device that has no comparable counterparts anywhere in the world — their assessment, and a defensible one.
The rekenrek: twenty beads, no place value, and a different job
Rekenrek is Dutch for calculating frame, and the standard one has twenty beads in two rows of ten, each row split five red and five white so that five and ten become shapes a child recognises instead of quantities a child counts. Its design is widely attributed to the mathematics curriculum researcher Adri Treffers of the Freudenthal Institute. The structural difference that matters: it is not organised into columns of increasing value, and a bead is worth one wherever it sits. So a rekenrek cannot represent 428, and was never meant to. It is an early-number-sense tool rather than a smaller abacus, and reading it as a weaker soroban is the usual mistake — it does a job the soroban does not do, at an age the soroban is wrong for. One caution worth stating plainly: no source sets a standard age or school grade at which a classroom should move from a rekenrek to a place-value frame, so anyone quoting one is quoting a preference.
The older frames, briefly
Search for abacus history and you mostly meet counting boards rather than bead frames — flat surfaces with ruled columns where loose counters were moved around, used around the ancient Mediterranean, alongside small portable grooved devices. They are genuinely interesting and they matter historically, but two things are worth knowing before leaning on them. Nobody teaches them as a working method today, and the descriptions of exact counter or bead counts vary between collections, which is why this page will not hand you a confident number for them. If you see a precise bead count for an ancient device with no collection or catalogue cited, be sceptical of it.
Which frame to learn if mental calculation is the goal
One research finding shapes this answer more than any heritage argument. Frank and Barner’s 2012 paper in the Journal of Experimental Psychology: General is the standard reference for the observation that mental-abacus users appear limited to holding about three or four abacus columns at a time, each column behaving like a distinct object in visual working memory. That comes from laboratory work with trained users rather than from a population sample, so it is a constraint on how the mental image behaves, not a score anybody should chase. What it tells a parent is simple enough: the frame you learn is the frame you will later picture with your eyes shut, so a compact layout with exactly one bead pattern per digit is an advantage rather than a matter of taste.
- You want mental calculation, exams and a ladder to climb: the soroban. One bead pattern per digit keeps the mental image unambiguous, and the Japanese graded exams give it that ladder: one proficiency ladder is administered jointly by the Japan Chamber of Commerce and Industry and the Japan Abacus Federation, and a second body, the League for Soroban Education of Japan, runs a parallel kyu-and-dan ladder plus a separate graded certification in flash mental arithmetic.
- You have family or cultural ties to the Chinese tradition, or you like the carry room: the suanpan. It does everything the soroban does. The mental image is simply a busier one to hold.
- You are teaching a young child what five and ten feel like: the rekenrek, and not yet a place-value frame. Its job finishes roughly where the soroban’s job starts.
- You inherited a schoty or are curious about one: learn it and enjoy it, but do not expect a curriculum. It is a fine everyday-arithmetic instrument with almost no modern teaching pipeline outside Russian-language material.
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