I love auction catalogues because you can find pieces that surprise you, that you haven't seen before or that are completely flying under the radar. One lot in the upcoming Phillips Geneva Auction struck all of the above in a truly special Rolex chronograph from 1937. I realized that this ref. 2917 is just one of a series of six(!) Rolex references for which production volume can euphemistically be called experimental. And down the rabbit hole we go...

October 25, 2023

Experimental Rolex Chronographs - The 1937 "Non-Oyster" Reference Guide


Marcus Siems     Marcus Siems @siemswatches
    Collector, Author, Data Analyst


Reference Guides:

Rolex Chronographs 1937 Non-Oyster - 1940s-50s - Pre-Daytona - Daytona


The next auction cycle has just begun and more and more catalogues are flying in. While many people browse the listings in search of the million-dollar lots or the next big trend my approach is a little different. I love auction catalogues because every so often you'll find a piece that surprises you, that you haven't seen before or that's completely flying under the radar. And yes to all of the above is exactly what I thought about one particular lot of the upcoming Phillips Geneva auction!

As lot 171 you'll find a Rolex chronograph that might look like the classic ref. 2508 for example at first glance but then you see the lugs - hinged, playful lugs, the sculptural Artdeco style. After a quick online search I realized that this ref. 2917 is just one of a series of six(!) Rolex references for which production volume can euphemistically be called experimental[1]. And this is where our story begins...


uber rare Rolex ref. 2918 chronograph from 1937The watch that sent me down the rabbit hole of crazy lug-shaped Rolex from the 1930s. A reference 2918 from the upcoming Phillips Geneva auction (Photo Courtesy ibidem).


1) The References

We're talking about a series of 6 references here. All share the same movement type (13''', based on Valjoux 23, 2-register, 30-min counter[1]), approximate case size (33mm diameter x 11mm height) and expressive lug shape. Further we can be quite certain that they came indeed as a series because basically all of the identified pieces are just a couple dozen case/serial numbers apart (but more on that below). The references are: 2916, 2917, 2918, 2919, 2920, 2937...


All six experimental Rolex chronograph references from 1937 - refs. 2916, 2917, 2918, 2919, 2920, 2937Figure 1. Examples from all six experimental Rolex chronograph references - refs. 2916, 2917, 2918, 2919, 2920 & 2937. You can see the distinct lug shape from all six different references. Photos Courtesy of Antiquorum, Christie's, Artcurial & Davide Parmegiani.


As you can see all six references are clearly set apart from the rest of Rolex's catalogue by their very Artdeco-esque lug design. The 2916 is single-hooded, the 2917 double-hooded, the 2918 with hinged lugs, the 2919 half-hooded, the 2920 with hinged faceted lugs, and the golden ref. 2937 with slim hinged lugs. The first 3 references appear to come in stainless steel only[2], while ref. 2919 and 2920 might have been produced in steel as well as gold[3] and ref. 2937 only in gold. Further, references 2916 and 2917 feature a stepped bezel while the others come with a more Calatrava-esque broad flat bezel.

The steel cases are hereby - in the instances I could identify hallmarks - stamped as SAR with a 7(!) tipped crown and "Rolex 27 Records Universels" (world records). It's not 100% clear what the SAR means (it might stand for "Société Anonyme Rolex"[4]) or why there are two additional tips to the coronet? Further, Rolex advertized to hold 27 observatory world records between 1935-37, which generally fits the approximate production and distribution of the entire series in 1937. The sole golden caseback inside further featured the casemaker hallmark of Favre & Perret (hammerhead #115). The case/serial number can typically be found on the outside of the caseback.


Casebacks from Rolex chronographs ref. 2916 and 2937Figure 2. Caseback markings on the six chronograph references for stainless steel (inside, left; outside, middle) and golden (inside, right) casebacks. Clearly visible are the matching writings "SAR" & "Rolex - 27 Records Universels - Geneve Suisse" as well as the casemaker hallmark "hammerhead #115" on the right. Photos Courtesy of Antiquorum & Artcurial.


2) The Dial

With vintage Rolex - and particularly from a vintage this old - it's always hard to tell which dial features were born with the watch and which might have been replaced over time. So I'm not trying to make a definite claim about genuity (would never do without holding each example in my hand). But what I'm trying to do is to establish a baseline for hands, markers, scales, lettering, etc. on the dials we could find.


Several dial versions on Rolex Non-Oyster chronographs from 1937Figure 3. Different dial variations on several Non-Oyster chronograph versions from the 1937 Rolex series. Photos Courtesy of Artcurial, Christie's, Heritage Auction, Antiquorum & Davide Parmegiani.


Dial Color. The most common dial colors appear to be white followed by black. Those are the two main alternatives but we could further find one salmon ref. 2920 and another gold/champagne colored ref. 2937.

Marker & Numerals. When it comes to the hour marker we find two main configurations: full numerals and 6-12 numerals with prism markers. The marker and numerals further can be luminous (particularly but not exclusively on black) or not as well as painted or applied (the latter is less common).

Hand Styles. We can find three common hand styles for these references - leaf (or feuille), baton and pencil/syringe hands. Pencil hands come on luminous dials including luminous material themselves. The baton hands are mainly blued steel but variations in gold and (grey) steel appear to exist, too. Leaf hands are predominantly blued (or grey) steel. Interestingly, the two sub-dial hands often dissociate on a single dial (same as in the ad below, too).


The three most prominent hand styles on Rolex 1937 Non-Oyster chronographsFigure 4. Three predominant hand styles - Leaf (left), Baton (middle) & luminous Pencil (right). Photos Courtesy of Davide Parmegiani, Sotheby's 


Dial Lettering. It appears the majority of these pieces is signed "Rolex - Antimagnetic" with Rolex underneath 12o'clock and Antimagnetic above 6o'clock. Hereby, the "Antimagnetic" lettering appears to come in various spellings: Antimagnetic & Antimagnetique - with and without blank or dash. We'll further see that the watches are signed either "Swiss Made", "Fab. Suisse" or both (rarely neither) inside, underneath or above the outer scales at 6o'clock.

Functional Scales. The classic layout on these pieces has been with three functional scales - an outer tachymeter (base 1000 units) and middle telemeter scale (km assigned) and another inner chronograph scale. However, we found at least two examples (ref. 2918 & 2920) with only an outer pulsation and inner chronograph scale, speaking for potentially different application areas. The scale font is (common for the era) straight with knurled-to-open 6/9 or Breguet-style.


Different Font and Swiss Made versions on the Rolex Non-Oyster vintage chronographsFigure 5. Example Font, "Antimagnetic" & "Swiss Made" versions for the lettering on Non-Oyster Rolex chronographs. Photos Courtesy of Christie's & Antiquorum.


Taken together, there's so much variation among these dials that almost each and everyone of them is unique. During our search we could identify only two dial versions that completely overlapped between pieces.


3) The Production

Now we come to the interesting bit that transcends the design... how common were these pieces? Well, I've already mentioned that they likely never exceeded a preliminary/experimental stage of production. This claim has been underlined by the close proximity of serial numbers from all these pieces dating their production to approximately 1937. And indeed for all steel executions we identified a serial number range from 031.644 to 031.794 over five steel references. This would account indeed to about 30 pieces made per reference.


Reference 1st serial* last serial* ca. production
2916 031.644 031.653 10-36
2917 031.670 031.703 34
2918 031.728 031.740 23-37
2919 031.753 031.774 22-35
2920 031.787 031.794 36**
2921+ 031.821 / /
2937 29.943 / /

Table 1. Overview over Rolex Non-Oyster Chronograph case/serial numbers as identified through us*. ** Production of ref. 2920 as assigned by Antiquorum Tokyo 1989+ There's a "standard" 33mm chronograph - equally rare but without compatible lug architecture.


Interestingly, the short production run and the low output volume is typically attributed to the "avantgarde" nature of the extraordinary design... Something that customers and the broader population hasn't been accustomed to.

"these unusual creations probably never went above the experimental stage, most certainly due to the uncertain commercial success of the revolutionary design.[1]"

I'd like to disagree with this assessment. Yes from a modern perspective these pieces are very otherworldly. However, during the 1930s and early 1940s - the time of the creation of the Non-Oyster chronographs - extreme Artdeco lug shapes and sculptural extensions to the watch case have been somewhat of a trend.


Several examples of 1930s Chronograph watches with extreme lug shapesAs you can see virtually every brand commonly producing chronograph watches during the 1930s has some sort of case design with - from a modern perspective - unusual and expressive lugs. It's the late Artdeco that drives this new era of casemaking. Photos Courtesy of Antiquorum & Christie's.


Virtually every brand that's been producing chronograph watches during the 1930s launched one or another form of these pieces. Expressive and - from a modern perspective - unusual lugs are actually the norm.

Further, Rolex even showed their creation off in a 1938 French advertorial. Combine this with the quite common "Fab. Suisse" marking it might rather speak for a French market only chronograph series... But whatever made Rolex stop expanding their production of the Non-Oyster series it probably wasn't about the pieces being too "revolutionary".


A vintage 1938 French Rolex advertorial featuring a Reference 2917A 1938 French market Rolex advertorial prominently displaying a ref. 2917 (upper right). Photo Courtesy of HIFI Archiv.


4) The Collectability Proposal

To me this experimental 1937 Rolex Non-Oyster chronograph series is definitely one of the most intriguing mysteries of the last couple auction cycles. It got it all: a set of amazing designs, extreme scarcity with under 200 timepieces produced in total, from one the most important manufacturers of the 20th Century! Overall, we thus got six references that make a prime collection centerpiece.

Nevertheless, you don't really hear much about 1930s Artdeco design in watches, Rolex or others, these days, do you? It's tough to find any reliable information - so building such a reference guide is the very first step to broad appreciation and demand (imho). Likewise prices for these outstanding collectibles are still comparably reasonable* - you're looking at $200-250k for all six combined (given availability). There's been a spike in prices in the mid 2000s but since then several of the references (some in good condition too) hammered for well under $20k...


Special Executions of the Non-Oyster Rolex Chronograph Series from 1937Three of the more uncommon dial variations from the Non-Oyster Series - potentially with some controversy around them, too. A sought after salmon dial ref. 2920 (left; I'm pretty confident about this one), the only known double-signed Bucherer ref. 2918 (middle; this one's tough), and a special red pulsation scale 2918 with serial number 031.214 (right). This last one is truly special (independent of the dial) as the serial is by far the first. So this one might be an earlier prototype or the serial could be a typo (031.714 would fit well the 2918 range) - both extremely collectible assets. Photos Courtesy of Davide Parmegiani, Watchrapport & Antiquorum.


This makes the upcoming Phillips auction all the more interesting. We've rarely seen such a great example coming to market. Factor in that the ref. 2918 appears to be the priciest of the bunch we're looking at a very pivotal timepiece in lot 171 (this exact piece sold for 81,000CHF back in 2011). As always: if the price is good we might see more pieces hitting the market soon.

After all, these pieces are (imho) simply stunning examples of a long forgotten time and design language. You rarely can get something as far away from modern watchmaking as these 1937 marvels. It takes a connoisseur of Artdeco chronograph watches but if you're into unique, extraordinary and "revolutionarily" designed wrist sculptures - the Rolex Non-Oyster series is a must have!



ultra rare Rolex ref. 2921 chronograph from 1937 in 33mm and flat bezel

Well, as it turns out there's even a 7th reference - ref. 2921 - with the same movement type, same case dimensions and equally produced in 1937 only with close case number proximity and outstandingly rare. The catch... it's a "standard" chronograph design, as in no architectural lugs but a stepped bezel. It's thus actually closer in design to the more "common" (and slightly larger) ref. 2508. The only ref. 2921 I could identify was sold by Antiquorum Geneva in 2012 (with case number 031.821!).



* Yes, that's far from peanuts but if you compare it to compatible chronograph watches with Valjoux movement - even without such elaborate case designs - and add the scarcity and historical relevance, these Rolex chronographs are a relative value proposition.



[1] Rolex Ref. 2916, chronograph, minute-counter; Antiquorum Geneva, April 2021;


[2] Rolex, Antimagnetique, Ref. 2918; Antiquorum Geneva, Nov. 1999;


[3] Rolex, Ref. 2919 'Half-Hooded Lugs', 'Anti Magnetic'; Antiquorum Geneva, May 2006;


[4] Hans Wilsdorf and Rolex; David Boettcher, Vintage Watchstraps;



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