The story begins not with watches, but with calculators. In 1946, Kashio Tadao founded a small workshop in Tokyo that made microscope parts and gears. His brother Toshio, an engineer, became obsessed with a different problem: replacing the slow, noisy, gear-driven office calculators of the era with something entirely electronic. In 1957, the Kashio brothers unveiled the 14-A, the world’s first compact all-electric calculator, built with just 341 relays. Casio Computer Co., Ltd. was born.
Through the 1960s and early 1970s, Casio fought through the brutal calculator wars, developing the LSI chip technology that would define everything that followed. When the quartz revolution opened the door to digital watches, Casio saw the opportunity immediately. The same LSI circuits that powered calculators could power timepieces. In 1974, the Casiotron QW02 became the first Casio watch, featuring the world’s first automatic calendar function. It was a calculator company’s answer to what a watch should be — not just a timekeeping device, but an information tool.
Six years later, in August 1980, the C-80 arrived. It was the first Casio wristwatch with a built-in calculator, featuring a keypad small enough for fingertip operation and eight-digit arithmetic capability. The original Finger Touch System circuitry could electronically determine the intended key when a user accidentally pressed two at once — a design consideration that only a company with decades of calculator expertise would think to solve.
By 1983, Casio pushed the concept further with the CFX-200, a calculator watch offering 25 scientific calculation functions and 12 types of unit conversions. That same year, the TC-500 introduced a touchscreen calculator interface, displaying virtual keys on the LCD that users could press through the glass. These were not incremental upgrades. They were proof that Casio saw the wrist as a platform, not a limitation.
The CA-53W succeeded the CA-50 in 1988, refining the design with improved water resistance while keeping the essential character intact. When it appeared on screen in Back to the Future Part II and Part III, it became more than a watch. It became a symbol of an era that believed technology should be accessible, affordable, and fun.
By 1984, just ten years after the Casiotron debut, Casio had shipped its 100 millionth watch. The calculator watch was never the highest-volume product in the lineup, but it was always the most symbolic — the clearest expression of a company that started with calculators and never forgot it.
