A to Z of Innovations at Expos: Radio-controlled clock

Expo 1970 Osaka – the first World Expo held in Asia – was a showcase of Japan’s rapid growth and its status as a country of technological innovation. Among the many cutting-edge creations on display, the Expo’s official clock system was one of the most impressive.

Selected as the official timekeeper of the Expo, Seiko presented its futuristic atomic pyramid clock tower – an enormous apparatus capable of counting on almost perfect accuracy, with an error rate of one second per thousand years. The Ultra-High Frequency (UHF) system was regulated by quantum mechanics, remaining stable against change in temperature, atmospheric pressure and even earthquakes.

The master clock was equipped with a wireless control system, using radio waves to simultaneously direct the 110 clocks in 50 locations around the Expo site, ensuring that they all worked in harmony and kept the exact same time. It was the first time that such a system had been put in place.