Mikko, Marko and myself are currently doing some work on Citizen’s six digit model number, i.e. in the format of 12-3456. This format was first used towards the end of the 1960s. We are trying to see if there is (any) logic to this system by collating information from our own collections and reference material that is available to us. I suppose it keeps us off the streets at night! 🙂
One immediate issue, which I noted some time ago, is that quite a number of models don’t have a model number at all – just a case number. It is a puzzle, at least for now, why Citizen chose not to give some watches a model number….as an example this pic shows some of the chronographs, two of which don’t have model numbers:
So, watch this space, and feel free to offer any ideas about the model number ‘system’!