G-SHOCK set a watch spec no one could meet — then invented the structure to pass it

In 1981, Casio engineer Kikuo Ibe (joined 1976) broke the watch his father had given him in a corridor collision. Watches were precision objects that shattered on impact — the industry competed on thinness — so Ibe submitted a 14-character proposal: 'a tough watch that won't break when dropped', leaving the structure plan blank. Executives approved it out of curiosity, and PROJECT TEAM Tough (Ibe, planner Masuda, designer Nikaido) was then obliged to actually build it.

Ibe translated the vague word 'tough' into three measurable limits — the 'triple 10': withstanding a 10-metre free fall, 10 atmospheres of water pressure, and a 10-year battery. After 200–300 prototypes and two years, rubber armor had grown from four attachment points to a baseball-sized lump that still failed. The breakthrough came from watching children play with rubber balls: if shell and center never touch, impact never reaches the center. The module floated inside a hollow shell on shock-absorbing supports, tested by dropping prototypes from a third-floor toilet window.

The DW-5000C-1A launched in April 1983 at ¥11,400 (tax-excluded), was slow to sell, then exploded across 140+ countries. Cumulative shipments have grown from 100 million-plus (2023) to 160 million-plus per Casio's current official pages, driven by a structure — not a material — that made the watch survive.