Casio Root 121-A & 121-L
Written by Accutron on 2016-02-06

Devices included in this entry:

Casio Root 121-A four-function calculator with square root (pictured in thumbnail)
Casio 121-L four-function calculator

The Casio 121 series is a family of compact desktop calculators introduced by Casio in the late 1960s and early 1970s, which competed against Sharp's QT-8 line of calculators. As indicated by their model numbers, 121 series machines have a 12-digit display. Earlier machines are fitted with Nixie tubes, while later iterations are equipped with discrete VFDs. The 121-A was the first member of this series, and featured a relatively compact but unusual landscape form factor with an asymmetrical layout and a woodgrain bezel. The subsequent 121-B and 121-K saw improvements in IC integration, but retained the 12-tube Nixie display.

Introduced in 1971, the Root 121-A is perhaps the most sophisticated member of the 121 family, featuring a concise NEC chipset capable of performing the square root function. Unlike the original 121-A, the Root 121-A has a more conventional form factor, with a rugged black plastic case and an aluminum bezel.

The model 121-L is a later member of the family, which introduced VFD technology to the series. The 121-L was initially manufactured in a 14-chip version and later in the 12-chip version featured in our collection. Unlike the Root 121-A, the 121-L is equipped with a memory function. Despite differences in technology and capabilities, the Root 121-A and 121-L share the same form factor and aesthetics.

Like many Japanese desktop calculators from the era, the Root 121-A and 121-L are equipped with a magnetic reed switch keyboard.

Casio Root 121-A four-function calculator with square root.


Root 121-A calculator, enlargement of chipset and Nixie display assembly.


Root 121-A calculator with carrying case and accessories.


Casio 121-L four function calculator.


Casio 121-L, internal construction.

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