The Collectors’ Guide to A. Lange & Söhne Datograph

a lange söhne original datograph platinum black dial with Roman Numerals reference 403.035
403.035 original Datograph

During its centuries of existance, the watch industry went through several paradigm shifts. It went from being utilitarian to functionally obsolete to luxurious, and as claimed today; art pieces and status symbols boasted with provenance and stories. Inevitably, the hardware part of the industry, the watchmaking also followed. It transitioned from putting out fundamental inventions where one could see their value with observatoire competitions and finally to gimmicky innovations to open up new markets and attract attention…

In more focus, one of the latest shifts within the industry was without a doubt the in-house trend that took place during the last 20 years; where the traditional Swiss style outsourcing components left its place to vertical integration. We started to hear almost every manufacturé introducing so-called in-house movements; which actually a considerable amount is the same movement with different brand stamps…

However, as Newton explains in his first law of motion: an object will not change its motion unless a force acts on it. Among many forces for the in-house production shift, there was a crucial one from a small town in Germany and this is its story: Datograph.

A Lange Söhne Datograph in platinum case with black dial reference 403.035
The first – platinum Datograph reference 403.035

The Background

A. Lange & Söhne came up with Tourbillon Pour le Mérite in 1994; signalling that it wants to fight for the highest echelon of complicated watchmaking. Yet, one hit wonders do not work and there are some quintessential complications a manufacture has to master in order to gain a presence in the broader market. One of those complications is, without a doubt, the chronograph.

In the famous business book Positioning – The Battle for Your Mind Jack Trout and Al Ries talks about a concept called Product Ladder. Basically; each step of the ladder is a brand name and each different ladder represents a different category. So, if you are late to the market as A. Lange & Söhne ws, you need to compete with an already established ladder in the prospect’s mind.

Now, please try to apply the product ladder theory to the watch industry and prospects’ state of mind during 1990s. Who do you have in mind when one speaks about a chronograph? Patek Philippe, Vacheron Constantin, Audemars Piguet etc. the usual suspects. Hence, for A. Lange & Söhne to step-out from such established competition from product point of view there was only one way out: Create your own ladder or disappear.

The ladder at the time – Patek Philippe 5070J. Courtesy of Amanico

Creating a ladder however is not an easy feat. A. Lange & Söhne needed to take a different approach to almost everything, except the established dominant design features such as chronograph registers, or pushers, tachymeter scale… But everything else had to be reconsidered. And A. Lange & Söhne found the area that it wanted to focus – it was not on the front, but hidden for connoiseurs.

In 1999 at the the turn of the century, after decades passing by without a new chronograph movement, a company that was merely 9 years old came up with the most unexpected – an in-house chronograph: caliber L951.1 of the Datograph Flyback. The in-house chronograph of such magnitude, architecture and finish was the new ladder. Just to make it more concrete, in 1998, Patek Philippe had just introduced the 5070 with the Lemania ebauche (which is also too small for the case). I love how the living legend Mr. William Massena summarizes this:

It is always amusing to remember that the most beautiful chronograph movement of the 20th century was made by Germans. They gave 98 years to the Swiss to try their best.

A note 17/02/21: Jaeger-LeCoultre’s Kaliber 829 preceeds the L951.1 by a year. Thank you @so.frech for the correction.

This is the watch that got me into watchmaking (no it was not my grandfather) more than a decade ago, and since then, it delivers the same excitement, everytime.

Datograph – 1999

Franken words are one of the most well-known linguistic practices in German. These are the words that are formed by the combination of couple of words such as, Fingerspitzengefühl – Finger/Spitzen/Gefühl. So, as a German company, Lange also followed the language and created the name Datograph – Date + chronograph.

Datograph first generation platinum 403.035

Sell your A. Lange & Söhne Datograph by simply contacting

Lange introduced the Datograph in platinum reference 403.035 at Basel Fair in a small, shared booth with siblings IWC and JLC in 1999. There was not a giant watch in the booth, as it is the tradition now; but a giant movement model, just to increase the rushing heartbeat of the Swiss Competitors and to give them the opportunity to closely examine what they would have to deal with. Michael Hickcox, a well known collector and a dear friend says:

A. Lange & Söhne Datograph changed the future of watchmaking right there and then.

First generation Datograph was produced between 1999 and 2011. Before diving deep into the watch itself, I’d like to talk about the rarity of certain references. The break down of the versions is as follows:

  • 403.035 – Platinum case, black dial – From 1999 to 2011
  • 403.031 – Pink gold case, black dial – From 2003 to 2005 (Dufourgraph)
  • 403.032 – Pink gold case, argenté dial – From 2005 to 2011
  • 403.041 – Yellow gold case, black dial – In 2008 limitation not given but I assume something around 50 – 60 pieces (Yellow Jacket)
  • 403.025X – Platinum case, silver dial – In 2004 limited to 10 pieces (Albino Datograph)

Of course, both due to being the first one and the most common version, the platinum Datograph with black dial is the most well-known and the face of the collection. Though please note that even if the reference was produced for 12 years, when you take Lange’s production numbers (5k pieces at most in those years) in account, it is considerably rare compared to most other brand’s flagship products which I think only a couple of thousands.

On the other hand, the rightfully famous Dufourgraph reference 403.031 was produced only for about 2 years between 2003 and 2005. The reference takes its moniker from Mr. Philippe Dufour, who repeatedly stated that the Datograph is the best chronograph ever made, which he owns one in pink gold.

a lange söhne datograph pink gold black dial dufourgraph reference 403.031
The elusive Dufourgraph – 403.031

Among the usual three, the reference 403.032, pink gold / argenté dial is the underrated one. If Datograph collection would be Metallica, this one would be the Jason Newsted of the group. No less talented, yet overshadowed by its predecessor. Indeed, the original platinum / black dial Datograph plays a huge part in the 403.032‘s inpopularity; because people think that the black dial version is the one to have for collectability purposes. It is true to some extent, however, the 403.032 is no less beautiful. In fact, in comparison, it is much more sober and present; hence it certainly lures its own crowd.

a lange söhne datograph pink gold silver dial 39 mm 403.032 rare review
Stunner. 403.032 – Courtesy of @dr.ho.rology

Another important reference is the yellow gold Datograph (ref. 403.041 – aka Yellow Jacket) which was produced circa in 2008 with an estimation of 30 pieces in total. It has an interesting story: During SIHH 2008, the executives wear the yellow gold Datograph on the wrist for testing the public opinion purposes; as they still do from time to time. As a result the watch never appears in the catalogues and only sells via private relationships. This important reference made its public debut for the first time in Phillips Watches Retrospective Auction and sold for over CHF 170k.

a lange söhne datograph yellow gold black dial yellowjacket 403.041
Reference 403.041 – a.k.a. YellowJacket. More than 30 of these were produced

Lange also made couple of special editions for executives with full black, blue and silver dials. In addition, as a common practice of early days, the brand launched a special edition Datograph for the infamous retailer Pisa Orologeria in Milan in a limited edition of 10 pieces – graced with a platinum case and a silver dial. If you ever see one of these available, please pull the trigger faster than Red-Kit as they do not linger around much – or better, let me know.

datograph pisa 403.025x in platinum case
10 pieces special edition Datograph Pisa “Albino”

Now, let’s dive deep into it.

Case – A Hockey Puck?

Coming from the positioning notion mentioned above; the brand’s co-founder Günter Blümlein was aware that everything must be aesthetically pleasant and distinctive to create a unique position in the crowded marketplace. Therefore, he started with the cases, wanted them to reflect the Teutonic, strong identity of the region with heft. He said; When handling our watches, I want the owner to get the feeling of closing the door of a Mercedes. Walt Odets, as he does to many things, explains this the best:

It was (Saxonia 34 mm case) twice the weight a gold watch its size ought to be. The buckle was twice the weight it ought to be. Even the sapphire back had more gold in it than two solid backs from anyone else.

However, for Datograph, the current round case was not the first choice of Reinhard Meis, chief designer at the time and one of the world’s foremost watch historians, and Blümlein. There was another design that ignited the fire of Datograph towards the end of 1993: A tonneau shape. Indeed, as you might understand, Datograph’s famous movement was designed later on according to the decided case and dial design.

a lange söhne datograph earliest design chronograph reinhard meis
From Reinhard Meis’ book Great Timepieces of Saxony – LANGE UHREN GMBH

Even though the case shape is different, please note that the lugs, proportions, hands, and that famous triangle formed by sub-dials and big date are exactly the same. This was the template that later gave birth to the legendary caliber L951.1. Also note that the work started all the way in 1994. To be honest, I would’ve loved to see this! Perhaps for the 25th year of Datograph as 25 pieces?

The first generation Datograph case measures 39 mm in diameter and a relatively hefty 12.8 mm in thickness. When you strap the watch, the density and weight of the platinum case is immediately there. Yet, upon enjoying it for some time, its solid feeling creates a dangerous addiction – causing many other pieces to feel hollow.

It is constructed on three different levels as the case back ring, case band and bezel. The case band is satin-finished and beautifully contrasts against the mirror polished parts. The pushers have fine bevels and gracefully polished.

Three step construction, with signature details worthy of a closer look.

As it is the case with most thick Lange watches, the case back is slightly raised then drops towards the sides. It is there to accommodate the movement but also a visual trick of thinness when observed from the sides. I must add that due to this design feature, sometimes, the watch does not sit right on the wrist.

The main differentiator however is the lug design. Upon carefully examining the point where lugs meet with the case, you are going to notice a notch. That notch, thus the lugs, is one of the characteristic elements of Lange cases, not given up even for the Odysseus. The idea was developed by Blümlein to individuate the cases compared to Swiss counterparts. Consequently, he asked the craftsmen to mirror-polish the notched areas. In order to achieve such a contrast, the lugs had to be separately finished.

As a result, A. Lange & Söhne lugs are screwed into the case after finished, which in return delivers this striking detail. Moreover, the curvature of the lugs helps the watch sit comfortably on the wrist. The lug width of the series is 20mm and buckle width is 18 mms.

Datograph Dial – A Masterclass

The Lange Datograph ( series) is a lesson on constructing a geometrically harmonious design. Sure, it was odd for its time. Lowered sub-dials and Roman Numerals for a chronograph watch, and even a big date? Yet, none achieved great gains without taking great chances. Here, the blend of these strange elements created one of the most characteristic and recognizable designs in watchmaking.

A closer look reveals the very-well thought out details. The reason for sub-dials’ below the center placement is to strike a balance with the big-date window. The three indications form an equilateral triangle with a central point being the pinions in the middle; which gives a perfect focal point. Moreover, the Roman Numerals form another triangle between themselves, hence beautifully balances out the indications.

Datograph’s dial is mathematically perfect, but not without a soul. That soul reflects as strong and sturdy rather than romantic, a perfect companion to its hefty case and baroque indices. The dials are crafted from solid silver. Simple, yet exquisitely shaped baton indices tastefully complement the complexity brought by Roman Numerals. The gold hands are relatively broad and lumed, enhances legibility while contributing to Datograph’s chic-sporty look.

Datograph in pink gold case with black dial Dufourgraph reference 403.031
The Dufourgraph – 403.031

The big-date window frame utilizes the respective case material and handsomely polished. It is a great example on how finish contributes the functionality – as the reflection caused by polished windows illuminate the deep seated discs and delivers excellent legibility. The thick window frames also hide the leveled placement of the date discs – which is apparent in Zeitwerk models.

The only critique I can swing towards Datograph’s dial is regarding the date discs: When the date is between 1-9, the left window stays blank. Although this is the same for all Lange watches with big date; it disturbs when the window is in the middle, as it breaks the symmetry for 9 days

A quick note: the date change for Datograph is gradual, not instantenous. So it is normal that your watch takes about an hour to complete the jump of the date windows.

Caliber L951.1

Datograph’s movement alone deserves its own 6000+ words article. Alas, as I already rambled a lot due to my extreme – sometimes dangerous admiration for Datograph, I am going to try to keep it concise without skipping any of the anecdotes and slight changes in movement throughout its lifetime.

From the movement’s reference number L951.1, we understand that the development started in 1995. It was the first movement of the year and the first iteration of the series. The end product is a result of a couple years of design, prototyping and construction period.

caliber l951.1 of the datograph flyback chronograph reference 403.035
The first generation L951.1 – the prototype. More on this later.

On the technical front, the caliber L951.1 is neither a groundbreaking nor an innovative movement. It is a traditionally constructed, horizontal-clutch (chronograph and running gears engage horizontally) column wheel chronograph mechanism. Nevertheless, what puts it in a different league is its incomparable depth in architecture, harmony of finish techniques, different colors and as Ray Hudson would say; exemplary curvature that can only be rivaled by Jessica Rabbit on steroids.

Before going into the depths of technicals and aesthetics, I’d like to start with the development process of this one of a kind movement.

The Birth of Datograph’s Caliber

As mentioned in the case section, Datograph’s dial design was already decided so the goal was to create a matching & functioning movement accordingly. The job was on the shoulders of the three legends who are a big part of what made A. Lange & Söhne what it is today: Reinhard Meis, Helmut Geyer and Annegret Fleischer. However, it was Meis who was involved with the movement in and out – from mechanics to aesthetics.

Coming up with any design is a rigirous process, requires draft after draft until the final decision. As one of the first drawings show, the caliber L951.1 is no exception.

caliber l951.1 early sketches of the chronograph movement design
From Reinhard Meis’ book Great Timepieces of Saxony – LANGE UHREN GMBH

You see, even though the first design carries a great resemblance to what was going to become the Datograph, it does not have its full functionality e.g. it has the flyback lever, but not the jumping minute counter bridge. Moreover, the caliber number is L942.0 – because the idea of precise minute counter was added in 1995, which then gave the movement its final form to work on.

It took years for the two movement constructors to make L951.1 a reality. As I have heard couple of times, especially the precise minute counter needed hundreds of re-design and many solutions to make it work properly. If you’d like to read more on this particular mechanism, here is the link to the patent attained in 1998 by Reinhard Meis..

Caliber L951.1 Technicals

The finished movement measures 30.60 mm in diameter, 7.5 mm in thickness. It beats at a traditional 2,5Hz and delivers 36 hours of power reserve. Furthermore, the caliber L951.1 employs a flyback mechanism and a jumping minute counter. Albeit relatively common today, please note that these were very rare feats for 1999. For better understanding, neither Patek Philippe chronographs – 5070, nor Vacheron Constantin chronographs were housing such sophistication.

Before admiring and writing poetry on its beauty, first let’s try to understand how does the Datograph, hence a chronograph work.

how does a chronograph work caliber l951.1

The processor of the caliber L951.1 is the column-wheel. It is the link between the pushers and the function we see. If you look closer, you are going to see that the clutch lever, zero-reset lever and the operating lever are all connected to it. The chronograph becomes active when the operating parts of the mechanism connects to the running movement. When the user presses the start button, column wheel spins forward and pushes the clutch lever’s tail in between the pillars. With this motion, the clutch lever moves horizontally and meshes with the chronograph wheel. To stop, pressing the button again, the clutch lever sits on the pillar again and disengages from the chronograph mechanism.

How about flyback? This mechanism makes it possible to stop and reset a running chronograph mechanism with a single pusher activation.

The two essential parts of the feature are two armed heart lever (3) and the coupling wheel (8). The process begins with the push (1) to the zero-reset lever (2). Upon pressing the button (1), the zero-reset lever is pressed downwards and a pin transfers this motion to the heart lever. The heart lever holds a pin that is in permanent contact with the claw shaped flyback lever (4). Therefore, when the heart lever is pressed downwards, it presses the flyback lever to the left; thus, the flyback lever presses the coupling wheel and detaches it from the chronograph seconds wheel (6) and stops the chronograph.

1815 chronograph caliber l951.6 flyback lever assembly
Flyback lever (4)

On its downward motion, the heart lever makes contact with the heart shaped cam (7). Since the cam is connected to the chronograph seconds’ wheel, when the heart lever’s tail (5) pushes the cams, the seconds hand goes back to the zero position. When the pusher is released, the heart lever is pulled upwards and the whole process starts in order.

Caliber L951.1 chronograph assembly
The chronograph seconds wheel with heart cam (7) above

Little known though, the caliber L951.1 was not born perfect. In time, both due to functionality and longevity, the movement went through some drastic changes. When introduced in 1999, it was made of 390 parts but to my knowledge, that movement never came out to production due to some reliability issues – thus born the second generation L951.1 with 405 parts.

There are numerous changes between generations on levers, springs and jewels. The simplest identification between the L951.1 generations can be made via operating levers. The first, experimental version has a straight lever whereas the second and most common version has a curved one. The movements within Datographs are the second generation and was in production for about 8 to 10 years. The final version of L951.1 hence the Datograph can be found after 2007-2008 till 2012.

Caliber L951.1 Finish and Architecture

There is a dangerous temptation that every Lange owner can easily fall into: Wearing the watch case back up. Herein, caliber L951.1, makes a very, very strong case for such inducement. The three-dimensional construction of the movement brings an unrivaled depth; offering a myriad range of angles, finish techniques and new things to discover with every glance.

The base ¾ plate as well as the chronograph bridges are made of German Silver whereas the chronograph work is made of steel. The contrast created by the German Silver’s warm hue and steel’s cold grey is delightful. I was awe-struck upon observing the work going into each and every one of these pieces. In this 30 mms diameter area, one can find 9 different finishing techniques.

Big brands – most of the time – polish most of the bevels by fast rotating, hand operated machine tools called touret. As they rotate thousands of times per minute, the process is much easier compared to complete manual hand-finish with files or wooden pegs. However, there is an area that these tools are useless: Sharp inward and outward corners. As if the caliber L951.1 was not awesome enough, it also delivers two direct proofs for the demanding handwork: Sharp inward corners and free-hand engraving.

datograph chronograph caliber l951 and hand finishing
Sharp inward corners on the clutch lever. Courtesy of @silent.reverie

Actually, after all these words of admiration and in-depth examination, Lange’s advertisement from 1999 perfectly encapculates what I am trying to reflect here:

Isn’t this the truth? Courtesy of Sascha Glitsau

As a final remark; one of the most celebrated specs of the movement is its pusher feeling and I assure you, the fame is not for nothing. The engineering and watchmaker’s prowess goes into creating such a buttery-smooth experience is beyond me; yet the results are easily comprehensible. It is very consistent, impossible to activate on accident yet silky smooth when needed.

first generation datograph caliber l951.1 in platium case 403.035

After almost 13 years of availability, Lange discontinued this modern grail in 2012 – only to breath new life into its successor.

Datograph Up/Down – 2012

The long awaited update to Datograph arrived in SIHH 2012: Datograph Up/Down. Here I must be clear that what I meant by long awaited is in terms of years; not in terms of production numbers. See, even if it was produced for 13 years, considering A. Lange & Söhne’s production numbers in 1999 and through the 2000s, Datograph remains as a considerably rare specimen.

The model is currently available in platinum (405.035) and pink gold (405.031). Datograph Up/Down’s task is a monumental one. It came to replace one of the most recognized faces of the brand and I think even with some shortcomings, Lange did a great job on modernizing the Datograph.

datograph up down power reserve in platinum 405.035
Datograph Up Down in platinum – 405.035. Courtesy of @awatchconnoisseur

The Datograph Up/Down measures 41 mm in diameter and 13.1 mm in thickness. Which means it is 2 mms wider and 0.3 mms thicker than the first generation. However, it has a considerably better diameter / thickness ratio; hence, it sits better on the wrist. Moreover, the lugs are shorter in comparison to the original 39mm version. This detail also helps to beautifully balance the increased diameter.

Datograph Up/Down houses significant differences from the first generation both on the front and the back. Let’s start with the dial side:

A Lange Söhne Datograph comparison 403.035 and 405.035 side by side
403.035 (left) and 405.035 with 2 mms in difference

The biggest changes on the dial are the removal of the Roman Numerals and the addition of the power reserve indication. Two changes I am not very fond of.

As mentioned in the first generation Datograph section, in addition to adding a distinct and a strong character, Roman Numerals were creating a brilliant balance to the upper-centered focus point formed by sub-dials and the big-date. Unfortunately, Datograph Up/Down loses this balance due to the removal of the Roman Numerals. Albeit the arrangement results in a cleaner and a simpler look, it creates too much blank space, even more so with the increased dial diameter.

Another point is that without the Roman Numerals to balance out the rather crowded lower part, the gravity’s effect on the dial becomes more apparent. This in return causes the power reserve indication to hang by itself, without any balancing element.

All in all, I would prefer the former instead of the Datograph Up/Down’s modernized, yet slightly empty design. However, got to give it to Lange’s deservedly famous attention to detail as the date windows and discs as well as markers are slightly enlarged to accommodate the bigger dial.

Caliber L951.6

As a result of the modernization mission, Datograph Up/Down comes with an array of significant technical updates. Compared to its predecessor L951.1, the L951.6 is technically superior in every way and equally stunning in beauty.

With the removal of the maltese cross (limits the energy transfer below certain torque to make sure optimal timekeeping) on the mainspring barrel and a new thicker mainspring, Datograph Up/Down offers 60 hours of power reserve – a 24 hours increase from the previous generation.

a lange söhne datograph up/down caliber l951.6 free sprung balance

Moreover, instead of regulated balance, the updated L951.6 has an in house free-sprung balance with in-house balance wheel with overcoil – which in theory delivers much better performance compared to its predecessor. Also, A. Lange & Söhne states that the isochronism when the chronograph is actuated is much better compared to the previous generation.

A. Lange & Söhne caliber L951.5
Caliber L951.6 on the move

Datograph Up/Down is a watch that is not fundamentally different from its predecessor – it does not need to be anyways. It incorporates small tweaks as a result of the changing design language of A. Lange & Söhne: Less baroque, more Bauhaus. Still very characteristic, and beautiful, just a bit less on both compared to the first generation, in my humble opinion.

Buying a Datograph

I would like to finish up with a quote from the founder of Ming Watches – Ming Thein:

“In many ways, owning a Datograph represents the end of the line for this hobby”

I cannot dispute against this. Datograph is the embodiment of the watchmaking craft in an area of one’s palm. An eternal dance between engineering and aesthetics. Still, to many, it is the best chronograph ever made.

On the market side; to my knowledge, 403.035’s retail price was 69,000 DM – €35k in 1999. Following 12 years, the price of Datograph went up to €62.6k – $80k in 2011. The price hike mostly took place in the final year of availability to the path on Datograph Up/Down. That is quite possibly to manipulate the second market and to get people ready for the new model’s pricing.

a lange söhne datograph collection comparison review 403.035 403.031 403.032 403.021
Courtesy of @silent.reverie

As of February 2020, in the second market, the platinum first generation Datograph (403.035) is in the mid $50k, has been gaining a solid traction. On the other hand, the Dufourgraph (403.031) asks noticable premium over its predecessor. In the last two auctions that it appeared, the pink gold / black dial Datograph sold for above €75k.

Good thing is that the pink gold / argenté dial (403.032) version is still flying under the radar and it can be found for a bit north of $35k.

Datograph Up / Down on the other hand, has a retail of $99k for the platinum (405.035) and $76,7k for the pink gold (405.031) version. The secondary market for the models offers a significant price advantage; both editions can be found for about $60-65k on average. Even a bit less and sometimes unworn with some research and negotiation.

In conclusion: Surely the term “value” is utterly subjective for every collector. Yet, for a watch of this magnitude, historical importance, such value – especially in the second market is unbeatable.

The Verdict

In broad context, the Datograph is one of the most important elements of the modern watchmaking history. For Lange, it is undoutably one of the faces of the brand, one of the watches that put them on the map and perhaps at top of the pyramid.

What I care about the most though; there is no other watch that one can put next to it and decide based on only small details, no. It is different and characteristic. It is not a derivative. Moreover, its movement is quite possibly the best looking chronograph ever made. These combined qualities put Datograph in a league on its own.

There is one question people have been asking for almost a decade: Original Datograph or Up/Down. Although it comes down to each one’s taste, a connoiseur and a dear friend @alangejourney perfectly answers the question:

This is similar to the evolution of the Datograph Perpetual! For someone deciding, the second generation is more of an introduction to the brand as it is now, and that might be better for someone starting out with Lange. But there is nothing comparable to having an example of “the piece that started it all,” and that tilts to the first generation.

In case you’d like to buy a Datograph, or sell yours, please kindly contact via Thank you.

Further Reading

Heated discussion regarding Datograph’s technical significance, if Lange cut corners and early days of the brand by none other than Walt Odets and Peter Chong: Lange Debate

The most comprehensive technical walkthrough on chronographs by Skyeriding.

Please do not hesitate to contact me either via Instagram Langepedia or if you have any additional information or correction. Thank you.

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