1971 · Single-Chip Pocket Calculator · Work 936 of 1,871
Behind the glass of a shop window in Tokyo on a January evening, on a small cushion of dark blue velvet a flat upright calculator twelve centimetres tall, its front matt near-black with a faint blue tint, a silver metal edge around its sides with a small chrome button, at the top a long narrow strip of soft red glow behind dark glass, a plain black plate across the middle, below it white and pale blue keys, all plain smooth and unmarked, a raised rounded bead along the lower edge, a black wrist strap lying loose beside it, a gloved hand resting flat on the cold glass, street lamps reflected in the pane.
What it was used for
The Busicom LE-120A is a Japanese pocket calculator; it went on sale in Tokyo from January 1971. It cost 89,800 yen, about 900 marks according to the Heinz Nixdorf MuseumsForum, and just under 400 dollars in the United States. The metal case measured 7.2 × 12.4 × 2.4 cm, the display showed 12 digits as light-emitting diodes, and power came from 4 batteries. A carrying strap was supplied to stop the machine being dropped. The Computer History Museum lists it as one of the very first genuinely pocket-sized electronic calculators.
What was new
What marked it was the calculating circuit: the Mostek MK6010L, a single device for the whole calculator. The consequence of this machine was not confined to Japan: Otfried Steger, the GDR's minister for electrical engineering and electronics, brought back an LE-120A as a souvenir of a trip to Japan in early 1972, handed it to the director of the Funkwerk Erfurt combine and asked him to find out how the GDR could make such a device. The result was the minirex 73, which was presented at the Leipzig Spring Fair in 1973.
What the sources leave open: Price and dimensions differ because the sources state different things: the HNF gives 89,800 yen and 7.2 × 12.4 × 2.4 cm, the collectors' archive Calcuseum 395 dollars, 123 × 64 × 22 mm and 205 g. The Computer History Museum gives only the year 1971. The HNF gives 2,100 transistors for the MK6010 but assigns that type to the Junior and the NCR 18-16; it gives no figure for the MK6010L in the LE-120A.