The Casio G-Shock DW-5600C, released in 1987, is the second generation of the G-Shock and the first of the 5600 series. It keeps the square resin case and shock-resistant structure of the DW-5000C, adding a larger display, an alarm, a stopwatch and a countdown timer, with water resistance of 200 metres. It runs a quartz digital module and, like the first G-Shock, was designed around the “Triple 10” targets of a ten-metre drop, ten-bar water resistance and ten-year battery life. I could not find reliable official figures for the exact case dimensions, so they are not stated here.

The 5600 shape became the most recognisable G-Shock design, often called the “Speed” model, and it is the form Casio has kept in production in many versions ever since. It was the model that carried the brand through the late 1980s and into the global boom of the 1990s.

Collectors value the DW-5600C as the start of the 5600 line, and clean early examples are sought after, as the resin and strap age badly. The original 1987 model is no longer produced, though successors with the same case shape remain in Casio’s range.