Soroban in Various Number Systems

The Japanese Soroban is a counting device that is still widely used in the present day Japan. In all likelihood it was borrowed from China in the 16th century. It is divided into two regions, of which the upper one is called the "heaven" and the lower the "earth". Unlike in the Chinese suan pan, each wire in the upper region of the soroban contains a single bead, that, when it is next to the (region) divider, represents 5. Originally, the wires in the lower region each contained 5 beads, but the redundant fifth bead has been dropped about 1920.

The number of beads, therefore, on each wire of the authentic soroban is 5 which is exactly half of the base (10) of the decimal system. This observations allows to expand the device to any positional system with an even base. The applet below implements that idea.

Please try switching to IE 11 (Windows) or Safari (Mac), for no other browser nowadays runs Java applets. If asked whether to allow the applet to load, click Yes - the applet is signed with a security certificate from a trusted company.

Soroban in various number systems

What if applet does not run?


  1. M. Gardner, Mathematical Circus, Vintage Books, NY, 1981

Related material

  • A Broken Calculator
  • A Broken Calculator Has Its Uses
  • Suan pan in Various Number Systems
  • Abacus and Its Relatives
  • Abacus in Various Number Systems
  • Pythagorean Triples Calculator
  • Napier Bones in Various Bases
  • Base (Binary, Decimal, etc.) Converter
  • |Contact| |Front page| |Contents| |Algebra| |Store|

    Copyright © 1996-2017 Alexander Bogomolny


    Search by google: