I’ve just added – finally! – a new page listing all the case material codes that Citizen used up to the late 1970s. It’s as comprehensive as I can make it, but there may be more codes out there, which I can add of course if they can be verified. Some of the codes are obscure and very rare – I’ve not ever seen quite a number of them. It looks like some were used for only a short while when new materials were first used. For example ‘TI’ was used for cases and bezels made from titanium carbide, but this was replaced fairly quickly by ‘UHA’ – Ultra Hard Alloy. Maybe this was to avoid any confusion between ‘TI’ and Titanium, which was first used in 1970.
As always, comments and additional information are very welcome 🙂
Here’s a quick link to the page: https://sweep-hand.org/citizen-case-material-codes-used-on-vintage-models-to-c-1980/