I’ve only seen one photo of this watch, in about 20 years of collecting — on the pocketcalculatorshow.com website.
Sanyo made/rebadged a lot of calculator watches in the 1980s, the most common being world-time, telephone directory, and basic calculator versions. One of my favourite calculator watches, the variation of the Nelsonic Grand Prix, Sanyo V, is far more rare.
The scientific calculator, though, might just be the rarest of them all.
And it’s actually two calculators in one. While other scientific calculator watches like the Casio CFX models integrate the scientific functions into the standard 8-digit calculator, Sanyo takes a different approach, most likely due to having fewer buttons than the Casios.
Pressing the Mode button takes you into the standard 8-digit calculator with addition, subtraction, multiplication and division functions.
Pressing Mode a second time gets into scientific calculator mode, where the division button becomes a function key to trigger the scientific features — Ln, Log, square root, Degree/Radian, Sine, Cosine and Tangent.
Since scientific calculations can take some time, the Sanyo removes all the characters and replaces the display with a capital ‘C’ while it’s calculating, before presenting the result – which is a pretty cool function and gives you an appreciation of how it’s putting the onboard memory to work a sometimes complex calculation. The Casios just blank the screen for a short time, but the Sanyo approach is quite unique.
Other functions on the watch are being able to view the time in 12 or 24 hour mode, day, date, month, year display, and a daily alarm. There’s no hourly chime or stopwatch but, to be honest, there is so much already squeezed into this amazing watch, it doesn’t need anything else.
A real rarity and excellent example of what could be achieved with basic electronics in the early 1980s.