Calculator Day

What Is Calculator Day?

Every March 20th is "Calculator Day" (Dentaku no Hi) in Japan. It was established by the Japan Business Machine Makers Association (now the Japan Business Machine and Information System Industries Association, JBMIA). It commemorates 1974, the year Japan's annual production of electronic desktop calculators topped 10 million units and became the largest in the world. That year also marked exactly ten years since the first Japanese-made electronic calculator appeared.

The "Calculator Wars" and Technological Innovation

From the 1960s into the 1970s, Japanese manufacturers competed fiercely to develop better calculators.

• Japan's first electronic calculator: In March 1964, Hayakawa Electric (now Sharp) announced the "CS-10A," an all-transistor-and-diode calculator, and released it that June for 535,000 yen. It weighed about 25 kg and cost about as much as a car at the time.
• Smaller and cheaper: With the adoption of LSI (large-scale integrated circuits) and other advances, calculators rapidly became smaller and cheaper, until palm-sized models costing a few thousand yen appeared.
• Casio and Sharp: Casio, Sharp and other makers competed with LCD displays, solar cells and ever-thinner designs. This rivalry, known as the "calculator wars," is said to have also helped advance LCD and semiconductor technology.

Calculators and Work

The calculator greatly reduced the effort of arithmetic and made office work far more efficient.

• Leave the arithmetic, focus on thinking: By handing tedious calculations to a calculator, people could spend more time interpreting numbers and making decisions.
• Dedicated calculators are still in use: Even now that smartphone calculator apps are common, dedicated calculators with easy-to-press keys remain widely used in accounting and bookkeeping.

Fun Facts About Calculators

• The "00" key: The "00" key common on Japanese calculators makes it quick to enter large amounts of money.
• Reverse Polish notation: Some scientific calculators, such as those from Hewlett-Packard, use a method where numbers are entered first, like "1 2 +," allowing complex calculations without parentheses.
• Solar-cell pioneers: Solar-powered calculators are one of the best-known examples of bringing solar cells into everyday products.
• "Dentaku" is an abbreviation: The Japanese word "dentaku" is short for "denshi-shiki takujo keisanki," or electronic desktop calculator.

Tips for Enjoying Calculator Day

• Turn your smartphone's calculator app sideways and try the scientific mode or other features you haven't used
• Learn how to use the memory keys (M+, M−, MR) to handle totals and subtractions more efficiently
• Go over your household budget or expense totals with a calculator and make the numbers add up
• Look into the history of Japanese calculators and a time when Japanese manufacturing led the world

A Piece of Japanese Tech History in the Palm of Your Hand

The calculator that cost as much as a car in 1964 was being produced at more than 10 million units a year just ten years later. March 20th is a day to remember that the humble calculator on your desk carries the history of Japanese electronics becoming number one in the world.