I'm trying to find information about this Longines watch, the Caliber is 12.68z but I think it's actually a 12.68zc.

 

Ummm, you're asking about what caliber that watch has, but the one thing you don't picture is the caliber?

 

12.68ZQ where Q stands for Quantieme (with date function). You change the date by pressing the pin. If you are missing the movement, it is mission impossible (it is an uncommon variant).

 

This is a ref. 5412 from around 1946, based on the batch number (23'127). The movement should be a cal. 12.68Z that has been modified to accommodate a calendar mechanism. As stated above, these are relatively scarce watches and finding a movement, hands, and crown will be difficult. Due to poor water resistance, many of these have refinished dials. Yours is worn but original. If you get a chance, it would be neat to see an image of the back of the dial. Below is a standard cal. 12.68Z (left) and a 12.68Z with the calendar mechanism.

 

Hi, I wasn't specifically asking about the movement (I didn't add pictures of the movement because it's currently being repaired). I just wanted to know any extra information about the 12.68 model, when was it built, how many of these watches were made etc.

 

Thank you, that was very informative. Here's a picture of the back of the dial:

 

Thank you for this image. The star on the back of the dial indicates that it was made by Stern Frères.

While the cal. 12.68Z was produced from 1929 and into the 1960's, this variant had a much smaller production run from around 1944 to 1950. There are a few references that contain these calendar movements but the most prevalent is 5412.

 

Thank you again for the information! Do you have any idea of how much one of this watches could be worth?

 

Nice find, here is a picture from the catalogue des fournitures.

 

Coincidence, I just saw one three days ago and had more or less the same questions. The owner is asking 500€.
I am in doubt, considering the dial condition, but on the other hand it is 38 mm. in diameter and quite original.

 

Thanks for posting this.

Difficult to say as these watches are quite uncommon and not well-known by collectors.

Thank you for posting these images. I believe that this could be a ref. 5758. This reference seems to be even less common than ref. 5412. The dial looks original, as does the second hand. I am not certain about the hour/minute hands. The pointer hand is very atypical. The crown looks like those of the period but I am not certain of its originality. Most calendars (ref. 5412) seem to be around 35/36 mm in diameter whereas the stated diameter for ref. 5758 is 37.5 mm. €500 does not seem unreasonable given the condition, though the possibly incorrect hands would bother me. Below is a ref. 5759 with correct hands.

 

@Amadeus If you happen to have an image of the movement, with serial number, I would be grateful to see it. Also, would you consider changing the title of this thread to something like, "Longines calendar 1940's"? This might help for future reference.

 

Production started at least in 1943 (I have a reference 5167 issued on 12/21/1943).

 

I read in Patrick Linder's book that the movement was produced from 1943 but I had yet to see an example from prior to 1944. Thank you for this information.

 

Here are some pictures of the movement:



The movement isn't assembled because it's still being serviced.

 

Now it is mine, partly thanks to this post and to several PMs asking me, if I was not interested, to pass the opportunity to them.
Diameter is 37,3 mm.
It looks like, considering the overall condition, that it must have spent some years without a glass or its bezel.
Here are some more pics.

 

Good choice @omegastar

 

Thank you for posting these pics. I have seen two other examples from the same batch (23'127) and the first four digits of their serial numbers are the same.

@omegastar Nice catch and great pics! The movement and case are in good condition. 37.3 mm is huge. It will be interesting to see what Longines says but I believe that this is a ref. 5758 from circa 1946.

 

Thanks. How do you get information from Longines ?
Mounir

 

You can request an extract here: https://www.longines.com/certificate-of-authenticity