Longines Case Numbers: An Introduction

Lépine
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Dan S Dan S
Is the number you called the "iteration number" the one sometimes stamped on the back of a lug?

The individual number is often stamped below the order number on the generation of watches after serial numbers on cases is discontinued.

The numbers on the lugs is not used until removable casebacks are used on later watches. And I believe they are also the individual number.

The individual number is the unique number assigned to the watch for an order.
 
DirtyDozen12
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Dan S Dan S
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/
upload_2023-4-6_21-31-9.png

SAM23242.jpg
SAM23382.jpg
MARCELS-MALL2-10.jpg

Source: https://www.ebay.com/itm/1344317539...b&brand=Longines&_trksid=p2047675.c101224.m-1
upload_2023-4-6_21-33-16.png upload_2023-4-6_21-33-53.png upload_2023-4-6_21-36-38.png upload_2023-4-6_21-34-24.png
 
upload_2023-4-6_21-31-9.png upload_2023-4-6_21-33-16.png upload_2023-4-6_21-33-53.png upload_2023-4-6_21-34-24.png upload_2023-4-6_21-36-38.png
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Dan S
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slowjms
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@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.

IMG_3017.webp IMG_3018.webp
 
J_pilot
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slowjms slowjms
@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.

IMG_3017.webp IMG_3018.webp

In this case, yes, this is a red flag. For later watches with order numbers on inner casebacks, they will differ. The length here clearly points to this being a serial, vs. an order number, which should match the movement.

Juergen
 
pike409
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Dan S Dan S
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.
 
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