Today’s watch was a very significant one for Citizen – launched in mid-1973 it was their first quartz model. Using the 8810, 8811 and 8821 movements, they were electro-mechanical calibres, like the Cosmotrons before them. In other words they were battery powered, with a quartz crystal regulating a magnetically driven balance wheel via mechanical gears. The result is a remarkable 115,200 beats per hour oscillation, and accuracy for the 8811 & 8821 variants of +/- 10 seconds per month, and just +/- 5 seconds per month for the ‘EFA’ 8810. These hybrid movements were soon replaced by full electronic movements – I have read that they may have been produced for little more than 6 months. They are rare, especially the EFA models, and are high quality pieces – they were very expensive to buy new. They all have a ‘jewel’ at the 12 o’clock position, with two more at 6 and 9 o’clock on the EFA version. Mine is from October 1973 and is one of the 8811 models:
And the movement:
Sweephand's Vintage Citizen Watch Blog 
Yes, these are rarely seen. I have the upper middle model, and the lower left (which was used as a donor for the other). My watchmaker could not believe the movement when he saw it. I’ve never seen the EFA model offered for sale, though a well-known collector has posted pics on Instagram.
Thank you! Interesting watch. What abbreviation is used on dial? Couldn’t read it. Is it GC? What it means? Thanks
Sorry for my late reply. The abbreviation is CQ – Citizen Quartz. Stephen
Thank you!