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Straps for vintage fixed wire lug trench or officer's wristwatches.

Blog: Rolex Oyster

Date: 27 November 2017 - updated to correct missing image

Copyright © David Boettcher 2006 - 2019 all rights reserved.

I make additions and corrections to this web site frequently, but because they are buried somewhere on one of the pages the changes are not very noticeable, so I decided to create this blog section to highlight new material. Here below you will find part of one of the pages that I have either changed or added to significantly.

The section reproduced below about the early history of the Rolex Oyster is from my page about Rolex. There is a lot more about Rolex and about the Rolex Oyster on that page.

If you have any questions or comments, please don't hesitate to contact me via my Contact Me page.

The Rolex Oyster

Rolex Oyster
Rolex Oyster.
Image by kind permission of and ©

In late 1926 Rolex launched on to the market a new watch with a waterproof screw-down crown and waterproof case. It was named the "Oyster" by Hans Wilsdorf, he said "because, like its namesake it could remain under water for an unlimited time without detriment."

To what extent was the Rolex Oyster an original Wilsdorf or Rolex design? There had been many previous waterproof watches reaching back as far as the mid nineteenth century, as described on my page Waterproof watches, but none of these had gone on to great commercial success. The Oyster was not the first waterproof watch, or even the first waterproof wristwatch (as was incorrectly claimed in Rolex adverts).

Wilsdorf appears to have been stimulated to create the Oyster by patent CH 114948 for a screw down crown granted to Perregaux and Perret in 1925. It would soon have been realised that the Perregaux and Perret screw crown design was essentially useless, because of the problems with the left hand thread, and it would have been Wilsdorf who cracked the whip to get the technicians at Aegler to come up with a workable design incorporating a clutch, reinventing an idea that had been patented in America in 1881.

The Oyster case was almost certainly inspired by the 1903 Borgel 3 piece screw case, the similarities are obvious and Rolex watches had been made using these Borgel cases, as well as the original Borgel patent screw case.

Although neither the crown or the case were original designs, it was probably Wilsdorf who had the idea of pulling these two ideas together and creating a waterproof watch. Why did the Rolex Oyster achieve commercial success when many earlier waterproof watches, even the war proven 1915 Tavannes Submarine wristwatch, had not?

Wilsdorf was not a watchmaker, he was a marketing genius who was prepared to invest so much on advertising the Rolex name that by the 1920s he had created a known brand from a name that didn't even exist until 1908. The previous designs of waterproof watches were created by watchmakers, and when they were not advertised and promoted they sank without trace. Hans Wilsdorf was a restless marketing genius who really propelled Rolex and the Rolex Oyster, his flagship product, towards the heights it eventually reached. He did this by spending huge amounts of money on advertising.

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The Earliest Oysters

Rolex Oyster 34303
Oyster Case Hallmarked Glasgow 1926 to 1927
Image courtesy of and © Ben Eastwood
Rolex Oyster Registration 1926
Registration of "Oyster" July 1926

The exact date that the Rolex Oyster was "in the stores" and available to purchase is not known. In the Vade Mecum Wilsdorf says "in 1927 the waterproof "Rolex-Oyster" was launched" but many people think that it was on sale in 1926. Wilsdorf acquired the patent that started his quest for a waterproof watch from Perregaux and Perret No 114948 in October 1925 and registered the name "Oyster" in July 1926, as shown by the extract from the Archives de l'Horlogerie shown here.

Dowling and Hess report that they have seen Rolex Oysters bearing the Glasgow Assay Office import hallmarks and the date stamp ā€œdā€ for 1926/27, and an image of one such case is shown here thanks to Ben. The Glasgow year date letter was changed on July 1 every year when new wardens were elected, so Oysters carrying the Glasgow date letter ā€dā€ were marked at the assay office between 1 July 1926 and 30 June 1927.

The case back shown here is stamped with "Swiss Federal Cross114948", the Swiss Federal cross and number of the Perregaux and Perret patent, and also "Patent applied for". The "Patent applied for" alongside the patent number 114948 is at first puzzling because the official patent number is not known before the patent is granted, so this cannot refer to that patent. It must refer to a patent that been applied for but not yet granted.

The application for a patent on the Oyster case was submitted on 21 September 1926, and was granted as CH 120851 on 16 June 1927. The design of the case was simpler than that of the crown, it simply needed a screw back and bezel, well established technology, and a thread on the pendant for the screw down crown, which a drawing in the patent shows was a right hand thread.

Evidently the design of the screw down crown and clutch mechanism took a little longer. The application for the patent on the screw down crown was lodged on 18 October 1926 and the patent CH 120848 granted on 16 June 1927.

As soon as the designs of the case and the improved screw down crown with clutch had been created, Wilsdorf would have wanted to get watches onto the market. The applications for the patents would have been submitted as soon as the designs were finalised. Inventors cannot reveal their inventions to the public before a patent application is submitted, this would allow someone to claim that the invention was not "original". However, as soon as an application is received at the patent office, its date and time of submission registered. When, and if, a patent is granted, that date becomes the "priority date" from which the period of protection of the invention runs. At the time in Switzerland that protection lasted for fifteen years, so it was in an inventor's interest to get products made and sold as soon as the application was in, rather than allow a year or so to elapse before the patent was granted.

The "patent applied for" legend in the case back must refer to the patents for the Oyster case and screw down crown. This means that the successful design of screw down crown with clutch must have been arrived at in early October 1926. The earliest Oyster watches released for sale must have been shortly after which, together with the dates of use of the Glasgow date letters, gives a range for Oyster watches marked with the Glasgow Assay Office "d" date letter hallmarks of late October 1926 to June 1927.

Early Oyster Serial Numbers

There is a table in the back of the Dowling and Hess book which suggests that, based on hallmark dates, early Oyster case serial numbers followed a linear pattern between 1926 and 1939. In my experience this does not appear to be correct.

There are two potential stumbling blocks with hallmark dates. The hallmark has the force of British law behind it and therefore the date letter will be "correct". However, remember that hallmark date letters span two calendar years, in the case of the Glasgow Assay Office from 1 July to 30 June, and that the hallmark date letter only shows when the case was actually hallmarked, not when the case and a movement were assembled into a watch; that was obviously later - how much later? Who can say — to some extent that must have depended on supply and demand, remember that in the late 1920s there was an terrible economic depression that culminated in the Wall Street crash and subsequent years of slow economic recovery. Expensive watches like the Rolex Oyster would not have been flying off the shelves!

Notwithstanding the hallmark date issues, the serial numbers in the Oyster case backs that I have examined seem to be almost completely random. This may be because Rolex at the time did not have control over what serial numbers were stamped onto the movements by the actual manufacturer, Aegler in the case of the Rolex Oyster. Aegler were supplying many different companies at the time and it appears that Rolex did not have sufficient influence to impose their own serial numbers, they simply had to accept whatever serial number the ébauche manufacturer allocated to the movement.

In later years, from the mid-1930s onwards, Rolex gained more financial influence over Aegler and eventually consumed the whole of Aegler's production, so the serial numbers became more organised.

In short, the serial numbers in early Oyster case backs that I have seen follow no pattern at all and seem to be completely random. If you have a better idea, then please let me know.

The section reproduced above about the early history of the Rolex Oyster is from my page about Rolex. There is a lot more about Rolex and about the Rolex Oyster on that page.

If you have any questions or comments, please don't hesitate to contact me via my Contact Me page. Back to the top of the page.

Copyright © David Boettcher 2006 - 2019 all rights reserved. This page updated August 2019. W3CMVS.