Beadbay: the soroban
Soroban vs abacus: what is the difference?
A soroban is one kind of abacus, the Japanese kind. Abacus is the general word for a frame of beads for counting. The modern soroban has one bead above the beam and four below it on each rod, the fewest beads that can show every digit from 0 to 9.
A soroban to try
One bead worth five above the beam, four worth one below it.
The soroban
Each rod holds one bead worth five and four beads worth one. That makes exactly one way to show each digit, which is why reading a soroban is quick and why its methods can be taught as fixed moves. The beads are shaped like two cones base to base, so a fingertip slides them easily.
The Chinese suanpan
The traditional Chinese abacus has two beads above the beam and five below on each rod, with rounder beads. The extra beads mean a rod can hold more than nine for a moment, and a digit can be shown in more than one way. The soroban came to Japan from China and was slimmed down over time.
The Russian schoty
The schoty has no beam. Its beads slide sideways on wires, mostly ten to a wire, and you count the beads pushed to one side.
Older sorobans
Older Japanese sorobans had five lower beads on each rod. The one-and-four layout is the modern one.
Which should I learn?
If you want speed and mental arithmetic, the soroban: with one way to show each digit, the picture in your head is always the same. The app and these pages teach the soroban.
Questions
Is a soroban the same as an abacus?
A soroban is an abacus, in the way a violin is a stringed instrument. Not every abacus is a soroban.
Why does a soroban have only four lower beads?
Four ones and one five are enough to show 0 to 9, and with nothing spare each digit has a single shape.
What does the word soroban mean?
It is simply the Japanese word for the abacus.