Jaeger-LeCoultre

INTRODUCTION: Let's focus on an interesting and fascinating topic, the Vintage JLC Chronometers. Why Vintage only? Because we can consider almost all the modern production, since 1992, as Chronometers. Here is what I wrote in the article dedicated to prec...  

We can already answer to one question: We didn't have to wait for wristwatches to see some Chronometers, at the Grande Maison. Another question receives an answer: The Cal 21 RV is the first Chronometer known from the Grande Maison. Let's see all that in ...  

I cannot believe the amount of work you had to do here. The pix are fantastic. The depth of information is astounding along with the history. I will have to bookmark this one I knew I would be panting on this. And now I see why you are panting! Your finge... 

As Chronometry is a theme dear to my heart. Thank you, once again, Joe. Best, Nicolas

A document that feels appropriate to add to this post. A 1949 ad - stating the results from the 1948 Chronometre contests... Notice the number in the ad: 464254 and 464260. Then look at the number of the the movements in your post! 464254 - it is the same...  

Unbelievable. Thank you SO MUCH, my friend. Nicolas

I compared the number in your photos and the ad! How often do you get to see the exact movement, 66 years later?! :) Best, my friend Blomman

BUT it is breathtaking to see such a thing! Best, Nicolas

: Here, it is indispensable to spend some time on the definition of a Chronometer. According to Mr L. Defossez, who published an article in the Société Suisse De Chronométrie, there was an evolution in the definition of a Chronometer: - In 1714, the engli...  

These to this fantastic post! :) Hope you forgive me, my friend... Best Blomman ...  

.. the notorious Blomman- special sleeve : long, deep and full of surprises, sometimes.. And yes, the Militaries play a certain role in chronometry reviews . Best, my friend ! hs

I can't help myself... The MIL's is a MUST for this theme! :) Best Blomman

... Purist. I just received a JLC pocket watch converted to a wristwatch. Will send some photos later! Tout le meilleur mon ami - Scott

Another time, another state of mind... In the Fifties, Humanity saw the most inspiring, crazy and enthusiastic projects and challenges, on Earth as well as in the Space... Science and Adventures. When it comes to Chronometry and Jaeger-Lecoultre, two date...  

Among all the watches from the Jubilé Collection, the most famous is certainly, and by far, the E 168. The strong interest of the Geophysic lies in the fact that it the the addition of History, Horology and aesthetics. Through this reference, Jaeger-Lecou...  

You know my love for the Geophysic and the Jubilé collection... Obsessed by the Geophysic...? Yes, you might say that I am...! :) Best Blomman ...  

A perfectionist after my own heart. Congratulations on the two Chronometers ... and for displaying them as they were intended. A

To say that this Chronometer is a mystery, is a sweet euphemism. No hint of its existence in the Lecoultre archives, since they were lost. But it has been mentionned in several documents, such as: The Geophysic Leaflet: A close up of a text, on the left p...  

I still haven't found one... But I do have some documents to share... Best Blomman ...  

This is the only watch where it's easier to find documentation that the actual watch! Best Blomman

Mine has the "torpedo" style indices but the hands are just like the Geophysic. Lance

Yes, the plural has to be used, as there were different Geomatics, made since 1962 to 1970 ( round cases ) and from 1970 to 1974 ( tonneau shaped case ) for a total of 4351 round cases produced ( 2000 in stainless steel, 1578 in yellow gold, 773 in rose g...  

Now you made me drool....! :) And the chronometre papers of the RG...! :) Best Blomman ...  

The Cal 906 is the last automatic chronometer movement produced by the Manufacture. In fact, JLC made 7000 Cal 906, since 1973, till 1975. Some were housed in JLC watches, others were provided to Vacheron Constantin for their Chronometre Royal " automatic...  

You made an Opus Dei :) That is indeed one big beautiful post about JLC chronometry filled with amazing data and gorgeous pictures Kudos! Time spent in making such epic post is truly amazing surely something to return to on many occasions. Gratefully your... 

I am looking forward to your first reference book. With this post, the sharp photos from your new Leica, you certainly have enough material to complete a couple of chapters. Signed copies of the new book for all Purists! You are truly the Master JLC Moder... 

I should also thank the JLC Heritage Gallery for their help. They provided me some amazing documents and Pocket watches! Best, Nicolas

For what this is all leading up to..... ;-) Dean

10th of April, 8 PM, Paris Time? ;) Best, Nicolas

Nicolas, 'the JLC-professor, my compliments. What an impressive post. I've never seen anything like this before on a watch-forum, and I've got a lot of forums under my favorites. Like we say in Holland, chapeau!! Well done. All the best, Bobbe

But, for sure the most Super Funky! :) Am I obsessed by JLC Chronometres...? YES, indeed I am! :) Again, Nicloas - thank you for this stunning post about one of my favourite topics! Best, my dear friend Blomman ...  

.. Congratulations, my Nordic friend ; very happy for you! - Both are nice, but I prefer the first, if you allow .. Best, hs

Yes, the 24000 is Super Funky! :) Thank you, my friend! Best Blomman

Fantastic Review, what an effort, BRAVO and thank you Nicolas:) Cheers Francois from Down Under

JLC was actually using the planets and solar system already in 1947... :) Best Blomman ...  

Nicolas, This post is magnificent. The scope and rigor of the research and writing surpasses many of the dedicated commercial watch blogs. Entries like your JLC Chronology epic are what makes 'prosite/PuristS great. Thank you; like 4J, I'm bookmarking thi... 

The funny thing is that that review will also help me on my articles to come. As for the Master Tourbillon, yes, it is in the - 1 / +6 sec per day range. Which are prudent specs. All the best, Nicolas.

.. actually have been devouring this well composed write-up, with so much of data, so many details and other valuable informations.. In reality, you kind of outdid yourself, unbelievingly so - also each "module" & part is something to read, re-read again ... 

To thank you for an fantastic post! This time you have really outdone your self! :) To me Chronometry is the essence of watchmaking. Yes, I know we are talking about Tourbillons, MR's and all of these high end complications... BUT, if the accuracy is not ...  

Without accuracy, we would systematically be too late to bid on these Watch auctions. ;) More seriously, what you are saying is Antoine Lecoultre's philosophy... First, work on accuracy, then on some sophistications / complications. Best, and thanks for t... 

My god, what did you say? Two years to prepare this post? Now I fully understand why. What a lot of data to find, to collect, to check and to cross check. Let alone the great quality pictures. Chronometry is one of the things I like most about watches and... 

Rgds. Juan

.......Ud se lo merece caballero, impresionante su estudio!! In my days when sailing the Chronometer are essential and without their accuracy could be here or there and sometimes beyond of track was very very ...bad! All the best My friend! Juan

Aaah, if you want to see a Geophysic in the real, I think it will soon be possible... ;) Thanks for your words of encouragement, my friend. Nicolas

Concise and exhaustive – very impressive, Nicolas! The only question that lingers: why did JLC mark only some of the 24000-42s as “CHRONOMETRE” on their dials but not all of them – extrapolating from the pictures that can be accessed on the web it might e... 

You saw the mention Chronometer on the 24 000 only on the Master Mariner dial configuration, maybe? This is the only configuration I saw with this mention on the dial. Not on the earlier 24 000, the one I posted. The MM 24 000 came in 1974, this is what I... 

... a handfull of digits from Ilja's (pictured in Zaf's book) with respect to case numbers making the case about 300 digits younger than the one you show in your post. Further the movement is about 250 Digits older than the one you show in your post. Stil... 

Trust me Nicolas! ;-) It is a pretty ordinary 24000-42 with blue dial (165). Here you go: JLC 24000-42-165 CHRONOMETRE Cheers, Christian ...  

The Master Mariner version. The same than mine with this mention, I never saw! Wow! Best, and thanks, Christian! Nicolas

... or I may be just ignorant: could you tell me the difference between a 24000-42 Master Mariner and an ordinary 24000-42 please. I thought that Master Mariner was nothing but a name for the very 24000-42 (and others). Christian

... the Master Mariner has the CHRONOMETRE imprint! ;-) Btw.: the Master Mariner 24000 in the 1975 blue/white catalog does not have the imprint. Christian

I got my watch from the original owner, located in the US. So maybe the lack of Chronometre imprint on dial is a sign of region the watch was originally sold. But I doubt to find enough origin details since watches tend to go trough several hands before e... 

... why wouldn't be US market watches signed CHRONOMETRE? Other JLC models were. The coloured 1975 catalog in the post shows a 24000-42-165 with the imprint CHRONOMETRE. With the case number of mine just a handful of digits from yours one could be led to ... 

are often a useful instrument to figure out, but in this case is to less material available. I made some amazing discoveries regarding the (J)LC Weems using statistics, but will -if ever- publish them with British Horological Journal. From the given produ... 

What makes a cal. 906 Chronometer on one hand a 'Master Mariner' while other with indeed same reference from the same line, as you state are non Master Mariner?! JLC had several lines of watches in the 70's. ie De Luxe, Vogue, Memovox, Master Mariner, Clu... 

... a Saudi Arabian emblem by the 9 (crossed swords and a Palm tree). Looks like Mehltretter's 24000-42 has been especially issued for some Saudi Arabian authority. Christian

But it is true that, as Master Mariner is not always written on the dial as it is a family name, it is hard to see the différences. I will post somethingon the MM family, one day. Best, Nicolas

This does not add any credibility as you play a simple lawyer's game by pushing a disclosure into unspecified future. Of course with intentional smoke-screen, pointing away from the question/topic by generalizing it into a wide theme. Bravo, but busted. M... 

Now, it has been said and written that some were MM. Is this due to the fact that some other watches were not mentionning MM on their dial and still are, I don't know. I never saw a MM 24000 which doesn't mean that I saw all and that I can deny the fact t... 

...lawyer's rhetorics, unspecified hear saying, no sources whatsoever. No mate, you are on the hook. Yet you consider, while before it was like a fact. Thats how false legends are born. You give no proof or even a hint since you can't, is this the way ser...  

That date will mark the tercentenary of the Longitude Act! I doubt that JLC will go for a COSC-rated watch for the tercentenary. But the rumours about an all new evaluation and certification of chronometric accuracy could make sense with respect to that d... 

...perhaps, global warming? Cheers Francois from Down Under

guess latest sun's outburst resulted some effects. Cheers. I.

To my eyes, it seems that there is an error on page 91, when describing the picture of the caliber P 478/BWSbr.....the caption says Caliber P 78/BWSbr.... so, the P 478 becomes the P 78??!!!! A discrepancy of 400!!!!LOL!!! Sincerely, does it matter?? Perh... 

… mark a mistake of yours: you obviously confused the number of a caliber with the movement number! The number of a caliber is nothing but the name of a caliber, used to distinguish different calibers - whereas the movement number is the production number...