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Discussion Starter #1
What vintage Seiko movements have serial numbers on the movements themselves, as well as on the case back?

It seems that KS automatic chronometers (5246-6000, 5626-7040 etc) all have numbered movements - these serial numbers are 6 figures, but don't match the 6 figure numbers on the case back. I guess that this is actually required for a certified chronometer as the certificate has to be linked to an individual numbered movement.

Non-chronometer 5626 movements aren't numbered if I remember. However, it looks as if ALL 5246 movements are numbered, even the non-chronometer ones (e.g. as found in the Vanac "specials"). However, the later 5256 "special" movements aren't numbered (and as far as I know none of these were certified chronometers).

I wonder if the non-chronometer numbered 5246 movements were actually made and tested to chronometer standards, but just not certified.

Is there any relationship at all between the movement number and the case back serial number?
 

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I have a Seiko Worldtime made in 1968 - movement 6117. It has the movement number on the case back and on the movement itself. It's of the era of 6 digit S/N.

 

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I have a Seiko Worldtime made in 1968 - movement 6117. It has the movement number on the case back and on the movement itself. It's of the era of 6 digit S/N.

That's not what the OP is talking about - it's that each chronometer grade movement is allocated an extra serial number, to be able to identify it's individual maker and history of calibration, because these movements were originally return to factory repair only.
This means that not only does the case have a serial number - so does each movement, and a normal non-chronometer grade movement only carries it's movement type number.
 

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What vintage Seiko movements have serial numbers on the movements themselves, as well as on the case back?

It seems that KS automatic chronometers (5246-6000, 5626-7040 etc) all have numbered movements - these serial numbers are 6 figures, but don't match the 6 figure numbers on the case back. I guess that this is actually required for a certified chronometer as the certificate has to be linked to an individual numbered movement.

Non-chronometer 5626 movements aren't numbered if I remember. However, it looks as if ALL 5246 movements are numbered, even the non-chronometer ones (e.g. as found in the Vanac "specials"). However, the later 5256 "special" movements aren't numbered (and as far as I know none of these were certified chronometers).

I wonder if the non-chronometer numbered 5246 movements were actually made and tested to chronometer standards, but just not certified.

Is there any relationship at all between the movement number and the case back serial number?
In the absence of replies - it might be an idea to nip over to the Seikoholics forum, as they have an unrivalled database on Japanese movements and an amazing knowledge base too http://seikoholics.yuku.com/forums/69/Japanese-Watch-Info-Database
 

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What vintage Seiko movements have serial numbers on the movements themselves, as well as on the case back?

It seems that KS automatic chronometers (5246-6000, 5626-7040 etc) all have numbered movements - these serial numbers are 6 figures, but don't match the 6 figure numbers on the case back. I guess that this is actually required for a certified chronometer as the certificate has to be linked to an individual numbered movement.

Non-chronometer 5626 movements aren't numbered if I remember. However, it looks as if ALL 5246 movements are numbered, even the non-chronometer ones (e.g. as found in the Vanac "specials"). However, the later 5256 "special" movements aren't numbered (and as far as I know none of these were certified chronometers).

I wonder if the non-chronometer numbered 5246 movements were actually made and tested to chronometer standards, but just not certified.

Is there any relationship at all between the movement number and the case back serial number?
I have some non-Chronometer vintage SEIKO with 6-digit serial on movement plate.

King Seiko cal. 4402A (mid 1960s)


SEIKO cal. 2220A hi-beat (early 1970s)


SEIKO cal. 2559A hi-beat (early 1970s)


Not sure what that means. My guess is those movements were tested before got cased in.
 

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Discussion Starter #8
Nice! It's somehow satisfying to have a serial number, it implies that someone, sometime gave the thing some individual attention.
 

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Nice! It's somehow satisfying to have a serial number, it implies that someone, sometime gave the thing some individual attention.
+1. I don't know what it meant on the non-chronometer models. But somehow I know they are special. :)
 

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Pictured is the movement from my KS 5626-7000. It's a non-chronometer 5626A. However, you can clearly see a serial number on the movement. I'm not sure if this makes my 5626 an more or less special, but she still runs +3.75/day after 45 years…..not too shabby if you ask me!
 

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