The 1973 No.10 Citizen dealer catalog introduces various new models and you can see the evolution of the range.
In 1972 Citizen introduced the calibre 7810, the world’s first electronic watch with a time signal setting mechanism, that was used on the Cosmotron Special models. If the time is within ±3 minutes of the hour, pressing the button at the 8 o’clock position will correct all the hands to the hour. If the time is outside of ±3 minutes of the hour, pressing the button will reset only the second hand to zero. The models utilizing this calibre can be seen on pages 16 and 17.
