Casio

In April 1946, Tadao Kashio established Kashio Seisakujo, a small subcontracting factory in Tokyo, with his younger brothers Toshio, Kazuo, and Yukio helping. In June 1957, Casio Computer Co., Ltd. was formed by the four Kashio brothers after developing Japan's first compact all-electric calculator. Casio entered the watch market in 1974 with the Casiotron, the world's first watch with an automatic calendar function. In 1977, the resin-cased F100 paved the way for mass production of lightweight watches. The G-Shock launched in 1983, designed by engineer Kikuo Ibe with a 'Triple 10' concept: 10-meter drop resistance, 10-bar water resistance, and 10-year battery life. Baby-G followed in 1994. The F-91W, released in 1989, became the most sold wristwatch in the world with annual production of 3 million units. Casio remains publicly traded on the Tokyo Stock Exchange.