Citizen’s Special Cosmotron was a World First

Citizen was the first Japanese manufacturer to sell an electric watch, in 1966, using a battery and printed circuit instead of a mainspring, powering a relatively conventional hairspring. As the technology was developed, they also produced one version in a titanium case – a world first – as a limited edition, in 1970. However, there was also one other ‘world first’ in the Cosmotron line-up, this time a special feature of the 7803 movement. It was known as ‘Just Setting’ and allows the watch to be accurately synchronised to a radio or TV time signal. Although the watch has a conventional ‘second setting’ function, the additional unique element of this movement is that the hour and minute hands as well as the second hand can be set if within ± 3 minutes of the 12 o’clock marker, using a button at the 8 o’clock position. Here are Citizen’s original instructions for this function (with thanks to whoever uploaded this to the internet):


And here’s a video of ‘Just Setting’ in action:

Known as the Cosmotron Special, these are very nice watches. Running at 36,000 beats per hour they are an accurate and unusual timepiece, with that rather unique feature


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2 Responses to Citizen’s Special Cosmotron was a World First

  1. Marvin says:

    Interesting watch. So, it picks up a timing signal then auto hacks to the correct time w/in the 3 minute segment? Once again Citizen shows off their penchant for innovation. Thanks Stephen!

    • sweephand says:

      Hi Marvin – the radio controlled watches were quite a bit later than this one. The time is synchronised by manually pressing the button at the 8 o’clock position whilst listening to the radio/TV broadcast of the time signal. Stephen

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