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Nippon Calculator / Busicom HL-21

Nippon Calculator HL-21

Nippon Calculator / Busicom HL-21.

Distinctive features: Hand operated, 'Odhner'-type rotary pin-wheel type calculator.  Manufactured by Nippon Calculating Machine Corporation (NCM) which became a very innovative company in Electronic calculators, producing the first pocket-size electronic calculator and changing its name to Business Computer Corporation (Busicom).

The model pictured: 10-digit setting register, 21-digit accumulator register, 11-digit revolutions register.

410 mm x 164 mm, 130 mm (16.5" x 6.5" x 5"), 4  Kg (9 lbs.).

Made in Japan.

Introduced in 1963.  Price in Britain in 1966 60GBP, reducing to 39 10s [39.50GBP] for educational users (about $US150 and $100 respectively).[1]

The '21" in the model name 'HL-21' appears to relate to the 21-digit accumulator register.'

This machine makes extensive use of plastics compared to similar models of the time by other manufacturers, and also of die-cast pin-wheels.

With the introduction of electronics, Nippon Calculator became Business Computer Corporation, known as Busicom Corp - see the name badges in the photographs above.  Nippon/Busicom were closely involved with Broughton and Company Ltd. (Broughtons of Bristol).

Label on Nippon Calculator HL-21
Label on Busicom HL-21

Early model

Late model

Inside Nippon Calculator HL-21

The mechanism of this machine is based on cheaper die-cast pinwheels, though these are more prone to wear, rather than machined brass.
Also, the casing of the machine is made of plastic rather than metal.

Nippon Calculator SM-21

Nippon Calculator SM-21

Nippon Calculator SM-21.

Kevin Vartanian has kindly sent the photograph above of a Nippon Calculator SM-21, which was introduced in 1956 and appears to be a predecessor of the HL-21.

For information on performing the basic arithmetic operations see Operating a Pinwheel Calculator in the "Collecting Calculators" section of this site.

For details of the pinwheel mechanism click here.

Busicom were the inspiration to Intel to produce the 4004 microprocessor in 1971. This evolved through the 8008, 8088, 8086, 80286, 80386, 80486, to the Pentium microprocessor.

So perhaps we could say that these calculators were the ancestor of the Personal Computer !!



  1. "Equipment Report", Office Methods & Machines, April 1966, p310.

Vintage Calculators

Text & photographs copyright, except where stated otherwise, © Nigel Tout 2000-2024.