When we look at modern mechanical wristwatches, we can quickly notice that most of them are equipped with a transparent case back. It’s a standard feature regardless of the price range and country of origin.
The high-end brands take pride in showing the perfect finishing on handmade movements. Kickstarter microbrands often show off an undecorated Miyota, which isn’t a pleasant sight.
Still, we think of it as something recent. Is it really? Nope.
The origin of display case backs
It’s hard to say when the concept of the display back was used in any watch. The earliest examples I’ve seen date to the 1880s. That concept was the “salesman sample” case.
It appears to have originated in the United States. American pocket watch manufacturers were known for high-quality finishing, even on basic movements. Damaskeening on the bridges, substantial chatons, high polishing on various parts, etc. It would be a shame not to show the customers what powers the watches they’re buying.
Salesmen, jewelers, and watch retailers often displayed the movement in a case fitted with a crystal on both sides. There isn’t any evidence that these movements were ever sold in such cases. So, a watch with a case like that is either a complete “salesman sample”, or has been recently assembled from a random movement and “salesman” case. These cases don’t appear to be uncommon and aren’t hard to find.
First display case backs in wristwatches
It doesn’t seem that display backs were used until the 1930s. Even in watches from this period, they’re very uncommon.
I’ve certainly seen such backs in the very first mass-produced automatic watches by Harwood. However, it’s hard to say if these were salesman samples or pieces from short production runs. Perhaps these aren’t even original to the watches.
Display case backs in mass production
In the late 1940s, more and more avant-garde designs were being introduced. This included what can be called a “suspended dial.”
The point of these designs was to create the illusion of a void between the bezel and the dial. The movement and dial were attached to the case by three-dimensional numerals. A domed hesalite crystal was installed on both sides of the case.
I’ve seen specimens made by Marvin, although it’s likely that other brands could have made similar watches.
Hesalite crystal as a dust cover
This is a solution I’ve only seen in the 1940s and 1950s Zeniths, usually belonging to the Sporto collection. A low-dome hesalite was fit over the movement, however, the purpose of that isn’t clear.
Theoretically, there were two advantages of that. Firstly, it allows a safe look at the movement, without the risk of dust entering the movement during an inspection. Also, the vast majority of Sporto models had press-in backs, and an additional cover for the movement slightly improved protection against all kinds of dirt and dust in daily use.
1960s and on
In the 1960s, Omega revived the concept of the “salesman sample.” They did so in watches exported to the cradle of display case backs – America. However, this time these watches could be bought.
The solution, called the Kleerback, was a domed hesalite crystal in the back of a few Seamaster models, powered by the calibre 560. I’ve also seen claims of the Kleerback having been used on Seamasters with calibres 550 and 563.
The 560 and 563 are essentially the no-date and date version of the same movement, and so the use of Kleerback on 563s is plausible. The 550, meanwhile, pre-dates any known mention of the Kleerback.
That said, I don’t believe cal. 550 Kleerbacks to be genuine pieces. These are likely cases intended for the 560 and 563, equipped with a random specimen of the 550.
Presumably, the Kleerback wasn’t intended to be a sales hit as such. Instead, the point could have been for the clients to see the movements in action at a dealer, and inspired by sight, buy any automatic Omega. Or, any Omega at all.
Sapphire and mineral backs only began to gain popularity in the 1980s. It has to be remembered, that this was in the midst of the quartz crisis. In the minds of customers, quartz was the thing to have.
Showcasing a nicely finished mechanical movement was one of the very few ways to have the public excited. Display backs were also used in watches with unexciting movements as well.
It may be, that the makers of these watches hoped that just the possibility of looking at the movement would be enough to attract buyers. Otherwise, it doesn’t make much sense. However, it’s still being done.
As mentioned in the very beginning, a lot of entry-level manufacturers do that. This doesn’t concern just the microbrands. Recently, even Timex did that in the automatic version of the Marlin reissue.
Currently, the vast majority of manufacturers offer watches with display backs. In the early 2000s, not even the ever-conservative Rolex resisted the fashion. The short-lived Cellini Prince models had a sapphire crystal over the brilliantly finished Formwerk.
There are even companies that sell display case backs for watches that initially weren’t issued with one.
Since the 1980s and throughout the 1990s, exhibition case backs were reserved for dress watches. Or, to put it simply, they weren’t used in tool watches.
Display backs in dive watches
Display case backs in dive watches have only gained popularity with the second generation of the Omega Seamaster Planet Ocean, where Omega decided not to conceal the new calibre 8500 under a solid back.
You’d think that a dive watch is the last thing you want to equip with an exhibition case back. In a piece made to withstand rough conditions, theoretically, it’s impractical. Just another thing that you need to have protected with gaskets. And, by extension, another thing that can go wrong, allowing water to enter the case.
However, display case backs are now used in watches with water resistance ratings as high as 600m and more. I guess it can be said that they’re here to stay as well.
Possible reliability issues are unlikely to force the concept out of use. The only thing that can do that is a change in trends.
The revival of the closed back
With the recent trend for vintage reissues, staying true to the original design seems to be highly valued by the public. Reissues like the Longines Legend Diver are wildly popular.
Longines has ETA ebauches finished to a very high standard. It wouldn’t be a shame to let people admire these through a display back.
However, it seems that in the market for reissues, there’s little demand for that.
The future of the display case back
I’d be surprised if the closed back would make a big return to anything except reissues. It’s pretty much there to stay in tool watches. It seems unlikely that exhibition case backs gain a foothold in purpose-built dive watches.
All the same, luxury brands like Omega are unlikely to fit modern casual, and dress watches with a closed back. With the emphasis currently on hi-tech solutions in mechanical movements, this wouldn’t be a logical move.
All in all, the way things are now will likely stay that way for a while.