In 1962 Citizen introduced the beautifully named Diamond Flake based on the 0700 movement. Why this name? well a diamond flake would be thin, and at the time the 0700 movement was the thinnest Japanese design, measuring just 2.75mm deep – beating the Seiko Gold Feather by 0.2mm. I say ‘beating’ because there was something of a race to produce the thinnest movements, following the fashion for ever slimmer dress watches.
Here’s an ad from the time:
The movement was made with either 25 or 31 jewels, and later a date version was made (2700 movement, 25 jewels). My example has the 25 jewels calibre:
The logo at the 12 0’clock position is unique to the Diamond Flake, and the narrow hands on this model emphasise the slender overall design:
The thin movement allows a slim case:
This is a hand winder of course, an automatic would have been necessarily thicker to accommodate the rotor and auto winding system. The gold finish of the movement indicates that this was a good quality model:
The case back, with production in September 1963:
Some models were depth rated to 40 meters, but these were essentially dress watches, wearing light and comfortable under the cuff.