Kazuo Kashio, chairman and CEO of Casio Computer Co. who played a key role in developing the G-Shock wristwatches, died of pneumonia at a hospital in Tokyo on Monday, the company said Tuesday. He was 89.

Kashio, a native of Tokyo, was the third of four brothers, who in 1957 founded the Japanese electronics-maker and commercialized the world’s first all-electric compact calculator.

He propped up the sale of the G-Shock products after Casio launched its signature, shock-resistance watch brand in 1983, seeking to change the notion at that time that watches are “fragile and valuable” items.

The G-Shock was initially only popular in certain markets, such as the United States, but it eventually became a global hit. The worldwide shipment of the watches reached 100 million units in August last year, the company said.

Kashio succeeded his older brother Tadao Kashio as president in 1988 and remained in the post until 2015 when he was replaced by his eldest son Kazuhiro and became chairman.

“By breaking free from preconceptions and conventional notions, we have conceived products that are truly needed and used our digital technologies to make them a reality,” Kazuo Kashio said in a chairman’s message posted on the company’s website.

He also emphasized in the message the importance of developing products that create new markets.

The company has released various hit products, including the compact digital camera QV-10 in 1995 that made digital cameras more affordable to average consumers. Its rivals followed suit in developing similar products.

Kashio also led the development of the personal calculator Casio Mini, released in 1972, according to the company.