Calculators, keyboards, and digital watches: the trio of inventions that made Casio a success.

In the Seijo district of Setagaya, Tokyo, stands the house where Toshio Kashio conceived many of the inventions that brought Casio worldwide fame. Today, the former home of the second of the four founding brothers of this electronics empire houses the Kashio Toshio Inventions Memorial Museum. The display cases feature the brand's first calculators, its famous digital watches, and the legendary Casiotone keyboards. You can also visit Kashio's original studio, with hand-drawn diagrams and personal objects that explain his way of working. In the garden, known as the Forest of Inventions, you can breathe the premise that guided his entire life: inventions can arise from necessity, but they can also be used to create new ones.

Today, the company is a giant capable of generating revenues of around €1.6 billion annually worldwide and employing nearly 9,000 workers. In Spain and Portugal alone, in 2024, the Japanese brand's subsidiary generated revenues of around €40 million. But where did the company's seed come from, and how did it come to clash with the winning trio of calculators, keyboards, and watches?

The beginning: a smoking ring

The origins of Casio can be traced back to the small family workshop that Tadao Kashio founded in 1946 in a country marked by the post-war era. There, he and his three brothers—Toshio, Kazuo, and Yukio—began repairing machines and manufacturing metal parts until, thanks to Toshio's ingenuity, they created their first success: a ring that allowed users to hold their cigarettes without burning their fingers. The spirit of combining utility and curiosity marked all their subsequent creations. The profits from this invention were used to finance the project that would forever change the history of home electronics: Japan's first compact electric calculator.

The idea for the calculator arose almost by chance. At an office supplies exhibition in the Ginza district, Toshio Kashio was fascinated by large electric calculators of foreign origin. They worked with metal gears, made a constant mechanical noise, and cost almost as much as a car, but he saw clearly that they represented the future. Back in the family workshop, he began studying how to reduce its size and cost. With the support of his brothers, he replaced the gears with electrical relays—small, current-activated automatic switches that allow calculations to be performed much more quickly and quietly—and devised a new numeric keypad, with digits arranged from 0 to 9 in three columns and four rows. It was a faster and more intuitive layout that quickly became a worldwide standard. After years of testing and more than a dozen prototypes, in 1957 the brothers introduced the Casio 14-A, Japan's first compact electric calculator. This invention not only launched the company but also opened a new era for Japanese electronics.

Towards clocks and keyboards

The success of the 14-A calculator taught Casio two fundamental lessons: that innovation was compatible with affordable sales prices, and that simplicity could also be big business. With these two principles in mind, the Kashio brothers began to think about how to apply them to other areas of everyday life. In 1974, Toshio applied his expertise in electronic circuits to the wristwatch and launched the Casiotron, the first model capable of automatically adjusting the calendar at the end of the month.

The other great leap came with music. Toshio, who saw parallels between calculations and sound—both are based on numerical patterns—wanted to democratize access to electronic instruments. In 1980, he introduced the Casiotone 201, a cheap and lightweight keyboard that could play the sounds of twenty-nine different instruments. This product launched the home music market.

Today, in a market dominated by touchscreens and smart devices, the brand has adapted to the new landscape by combining nostalgia and innovation. Its strength lies in understanding that simplicity, when applied well, is also a form of avant-garde.