Definitely useful - thanks much! Though I own more than a few Eterna, I have, for some reason (and in stark contrast to Longines), not requested information on them from the manufacturer. It's nice to see that they are being helpful, even though such help won't directly benefit their bottom-line.

The qualifications that you make are actually, in a sense, somewhat predictable. I say that because, of course, no one working at any of these manufacturers could have ever dreamed that collectors would, 50, 60, 70 years later, be interested in such minutiae.

 

Very very interesting. Thanks for sharing.

 

Many thanks - certainly seems to align with some of my watches:

140T - Stainless 1408U hand-wind

162T - Stainless Concept 80 (sorry no photo)

438T - Gold-plated Eterna-matic 1000

410T - Gold-plated Eterna-matic 1000

306IVT - Gold-topped Eterna-matic 2000 Centenaire 71

Unfortunately they're the only ones where I've noted the case references - I'll need to pop the back off my other watches to add any more examples...

 

Most Eternas from the 1940s and early to mid 1950s didn't have the number on the case. Just like 1930s-1940s Omegas, both the movement and the case had a serial number only, with the reference number only being in the factory documents for a particular watch. For watches without reference numbers stamped on the case, you'll have to contact Eterna (as I've said before).

 

Hi! Thanks for this super useful thread! I’m trying to identify an eterna watch. I found a four digit number AO14 on the clasp and wrote to eterna as suggested. They said that usually vintage watches had a 7 digit number and they don’t know what the 4 digit number corresponds to. Are you saying that you think it’s a serial number and not a reference number? Do you have idea what it would correspond to? Might there be a 7 digit inside the watch or you think that it would only be on the papers that accompagniez the watch? Thanks so much!!

 

Following that pattern, a ref. 106 would be a steel, round watch with a press-in back, 106 B - the same, only on a bracelet, and a 106 T or 106 DT would be steel, round, have a waterproof case, but would originally have been offered on a leather strap. Though if they would feature a flat dial as well, would the reference become 106 FT or 106 FDT? Dunno. I also don't know, if the letter code always has to be three letters, or not.

Great stuff--thank you. Quick question--how did you deduce that ref. 106 referred to a press-in back, as opposed to a screw-in back?

I'm glad to hear also that the Eterna after sales office is so responsive. Given their well-documented problems recently I've been wondering how much time and effort they could devote to people who don't buy new Eternas.

 

And a quick answer: by simple deduction. "106" on its own means "stainless steel, round case." Since a waterproof case (screw-in back) would have a T or DT suffix, 106 without T or DT suffix stands for a non-waterproof case. With a press-in back alright.
As a matter of fact, I recall an Eterna posted here in F11, where the owner did contact the manufacturer, and it turned out to be a ref. 106. It had a press-in back, if my memory serves me well.

 

Elementary!

 

excellent info, thanks for sharing

 

I have an ETERNA MATIC watch with reference 833 2015 41 stamped on the back cover.
Can you help to identify the watch and also where can I get it serviced in South Africa?

psadler@salene.com

 

I have an eternal magic sahida it has 465 stamped on the inside of the case 1078 on the corner bottom left side4624747 on the back

 

Recently, after contacting Eterna to get to know more about my second vintage watch made by them, I was surprised to find out its reference number- 106 BDT. OK... No, wait - my 1952 Eterna has the very same reference number. And they're two very different watches! So I've decided to ask a few more questions, as I have suspected there's something more to these numbers.

The after sales department at Eterna has confirmed, that there is a system to their reference numbers, and the very helpful and communicative people there have kindly provided me with a scan of the guide to these, straight out of the archives.

Following my request, Eterna has allowed me to publish this chart, as a reference for other collectors - to help them understand the apparently (until now!) meaningless reference numbers of their watches.

So, ladies and gentlemen, here it is!
View attachment 12531177
*In case the image does not display correctly, right-click on it, and open it in a new tab.

A Brief Caveat
It is of vital importance to understand, that this chart will only allow you to understand a known reference number, which number you can obtain by contacting Eterna about your watch (will take 1-3 weeks for them to reply, but if your hunger for knowledge can't - like mine - be satisfied until you get to know all you can know about your watch, it's worth it...and it's free of charge).
You can't use it to determine the reference number only by matching the features of your watch to the chart.

Now, why not?

Quite simply: because you don't know, which features of a particular watch did Eterna consider to be the ones of priority, when assigning the reference number.

How Does It Work?
The first number is just the case material - well, so that part of the reference you can find out on your own. The two digits that follow indicate the case style - sadly, that part is not provided. I can only assume, that it may be somewhat more extensive than this chart alone. The letter code lists the features that set the model apart from another model sharing the same three-digit number.

A case study:
Why, let's look at the reference of my two watches- 106 BDT.

1 - stainless steel
06- case style, here (according to Eterna) it means a round case (however, as I've said, that's the part that's sadly not included in the resource)
B - a metal bracelet. Well, now I know that both of my watches originally came on bracelets, and I can only hope that one day I'll find a period-correct one to fit at least one of my Eternas. Sadly, no records about the original bracelets (references, catalogues, any documentation) exist.
DT - a waterproof case (yeeees, the Eterna waterproof case that I'm so fond of).

Following that pattern, a ref. 106 would be a steel, round watch with a press-in back, 106 B - the same, only on a bracelet, and a 106 T or 106 DT would be steel, round, have a waterproof case, but would originally have been offered on a leather strap. Though if they would feature a flat dial as well, would the reference become 106 FT or 106 FDT? Dunno. I also don't know, if the letter code always has to be three letters, or not.

Now, until you've got to know the reference, you can't really have an idea of which features have been considered a priority in terms of the letter suffix. For example, both my Eternas have flat dials - there's an "F" code for the flat dial, yet it's not included in the reference number, which only highlights the waterproof case and the bracelet. If any of them would have a narrow bezel, what would be the priority? The bracelet? The narrow bezel? The flat dial? I don't pretend to know the answer to that.

Summary
I know, that certain ways of looking at this material might suggest, that it's insufficient. However, as far as I know, no resource on the Internets has offered any insight into the topic, and this thread may well be the first to do that. That said, while it's not be a big database or a complete guide to identifying a vintage Eterna, it's the next best thing in terms of the reference numbers. Without contacting the manufacturer, it's not of much use anyway, but I hope that those of you who know the reference numbers of their watches will find it helpful.

I'd also suggest, that those of you who know the reference numbers of their watches post them up here, to turn it into sort of an identification guide. Those of you who don't - you can get the number, and then post the watch and the number here.

I hope that you found this thread interesting, and that it will at some point turns into a "database" project.

Interesting info. Thanks. I may have an exception to this key for the Eternamatic I own. The serial number on the movement is 4304248, per one dating guide, which would indicate that the movement is from 1959. The inside of the case back reflects a series of numbers (no letters), 593849. The case has Eternamatic engraved above the number. There is no caliber number referenced on the movement itself that I could identify. Only "17 jewels", "Swiss" and "adjusted two positions".