The abacus (plural abaci or abacuses), also called a counting frame, is a hand-operated calculating tool used since ancient times. Today, abaci are often constructed as a bamboo frame with beads sliding on wires, but originally they were beans or stones moved in grooves in sand or on tablets of wood, stone, or metal. The abacus was in use centuries before the adoption of the written modern numeral system and is still widely used by merchants, traders and clerks in Asia, Africa, and elsewhere. The user of an abacus is called an abacist.

This abacus in our collection was manufactured in China under the "RED Lion" name and appears to be a promotional item from IBM. It is a bi-quinary coded decimal style abacus, which is used in many abacuses, and in some early computers including the Colossus. The term bi-quinary indicates that the code comprises both a two-state (bi) and a five-state (quinary) component.

Manufacturer: Red Lion
Date: Unknown

This exhibit has a reference ID of CH30276. Please quote this reference ID in any communication with the Centre for Computing History.

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