Is the number you called the "iteration number" the one sometimes stamped on the back of a lug?
Is the number you called the "iteration number" the one sometimes stamped on the back of a lug?
No. As far as I know, the numbers that appear on lugs are individual numbers within an order or iteration. Below are two examples. I added labels for clarity.
Source: https://www.marcelswatch.com/en/product/vintage-longines-6242-sei-tacche-1951/
Source: https://www.ebay.com/itm/134431753915?_trkparms=amclksrc=ITM&aid=1110006&algo=HOMESPLICE.SIM&ao=1&asc=20200818143230&meid=c00d5f6ab0a14561a9d46ec127be9a41&pid=101224&rk=2&rkt=5&sd=114025226623&itm=134431753915&pmt=0&noa=1&pg=2047675&algv=DefaultOrganicWeb&brand=Longines&_trksid=p2047675.c101224.m-1
@DirtyDozen12 thank you so much for the info. I have a question, is it the case serial number always should match the movement serial number? See below example:
This is the same watch, but case back “serial number” doesn’t match movement serial number. Is this concern for watch’s originality? Thanks.
Thanks, I misunderstood what you meant by iteration number. 👍
Hi this is exactly what i am looking for.
I understand what the four digit reference number means in he case back.
I dont understand what iteration number indicates. For example the 4 in your picture. mine says 2.
Does the individual number has anything to do with how many were produced of that reference or its an unrelated number?
I am looking for information to determine how many were produced of a watch that is why i am asking all this. 99% its a one year only so would be neat to know how many were actually made.
Any help is apprechiated.
Thank you.
But for most of these case reference changes there is no obvious change in the physical design, and the fact that they all seem to happen at the same time (1970 or 1971) suggests that there's another explanation.
According to "At the Heart of an Industrial Vocation" (Patrick Linder, 2007)
Interesting observation. I wonder if it could be related to the movement? According to "At the Heart of an Industrial Vocation" (Patrick Linder, 2007), Longines came out with the caliber 430 in 1967. They then came out with a revised version, the caliber 6641, in 1972. Such a change seems consistent with the dates of the catalog images you showed above. I wonder if you have seen examples of references 8308, 8309, or 8317 with caliber 43x?
EDIT: P.S. My theory seems to be incorrect as I quickly found multiple examples of ref. 8317 with cal. 431.
This is something I would like to understand too, although my own focus is on late 1960s / early 1970s watches.
The case references on the insides of the casebacks always seem to be followed by a single digit iteration number in this period. There does seem to be some temporal sequentiality to it, i.e. the later a watch of a particular reference was made, the higher the number, but this doesn't always seem to be consistent (but maybe apparent inconsistencies are just due to swapped casebacks?).
I have seen nothing to suggest that there are any physical differences between cases with the same case references but different iteration numbers (except perhaps the addition of engraved designs on the back, with these being missing in most examples of iteration 1, but this could simply be coincidence of design change with iteration number progression).
Therefore I think your idea of the iteration number tracking how many examples of a particular reference were made is not a bad one. As the serial number is not specific to case reference, you can't use that to know how many watches of a given reference were produced in a given period. So it would make sense to have a case-reference-specific "counter".
But even assuming this is true, how many watches would be represented by a single digit change of iteration number? And would this figure be consistent across different references?
I think what DirtyDozen12 calls the "iteration" number following the reference number may be a group code for different dial designs within the 4-digit reference number.
