Review: Jaeger-LeCoultre vs Zenith - Ultra Thin

Imagine that the following describes the watch you really, really want: 40mm in diameter, steel, design as uncluttered as possible without compromising legibility, a sub-dial for the seconds and—most importantly—an ultra-thin case housing a beautiful in-house movement that can be seen through a sapphire case back. Oh, and a silvery-grey finish to the dial to top it all off, why not. Okay, perfect. With this very specific set of requirements, it shouldn't be too hard to choose the right watch ... should it?

Jaeger-LeCoultre Master Ultra Thin Small Second 1358420

The Jaeger-LeCoultre Master Thin clearly fulfils our fictitious wish list, and then some. At 8.62mm thick it won't just fit under a cuff so much as it'll disappear up it, and that's thanks to the wafer-thin calibre 896 squeezed inside.

Following the work of watchmaker Jean-Antoine Lépine—a man who ditched a sizeable chunk of the standard pocket watch mechanism and by doing so changed watchmaking forever—Jaeger-LeCoultre has long been known for producing clever solutions to watchmaking problems.

The Jaeger-LeCoultre Master Ultra Thin in steel

This is why the brand has for a long time been the watchmaker of watchmakers, supplying movements to the likes of Patek Philippe, Audemars Piguet and Vacheron Constantin. Yes, you heard that correctly: Jaeger-LeCoultre has furnished every single one of watchmaking's top three with the engines to their timepieces.

You could say that Jaeger-LeCoultre is as much an engineering firm as it is a watchmaker, setting the precedent just a decade in by developing the first instrument capable of measuring one micron—that's a thousandth of a millimetre. You know a watchmaker means business when it redefines accuracy—literally.

But what use is the ability to measure a micron if you're not willing to use it? Well, in 1907, following a succession of record-breaking achievements that are too numerous to mention here, Jaeger-LeCoultre put the device to superb use with the calibre 145, the world's thinnest movement.

The watch measures in at a scant 8.62mm thick

It was actually a challenge set by Edmond Jaeger to Jacques-David LeCoultre before the two became partners, and it measures in at a slight 1.38mm thick. To put that into perspective, over a century later and with the benefit of advanced metals and high-tech milling machines, the automatic calibre 896 inside this Master Ultra Thin is over double that at 3.98mm thick.

The calibre 145 was quickly followed by the world's smallest movement, the calibre 101, which, at 14mm long, 4.8mm wide, 3.4mm high and one gram in weight, was smaller in size than a shelled peanut.

So, what you're looking at here is the culmination of almost two centuries and over 1,000 calibres' worth of perfection. It's not a record-breaker—although Jaeger-LeCoultre has that as well in the Master Ultra Thin Squelette—but it's as far as is practical to go for a watch that's intended to be worn every day. Or is it?

The in-house calibre 896 provides power to the watch

Zenith Ultra Thin Elite 65.2010.681/91.C493

Thirty-two years after Jacques-David LeCoultre's grandfather Antoine set up shop, about the time when he and his son Ellie had finished construction of their new factory in the Vallée de Joux, a new watchmaker appeared down the road in Le Locle: Zenith.

Despite Jaeger-LeCoultre's head start, Zenith managed to earn its fair share of accolades, including a gold medal at the Paris Universal Exhibition, over 235 awards for its class-leading calibre 135, and of course the introduction of the world's first integrated automatic chronograph, the much-documented El Primero.

The sunburst dial on the Zenith is ultra clean

Over 150 years, Zenith has been giving Jaeger-LeCoultre trouble, and it's showing no signs of stopping now. You see, the Ultra Thin Elite not only matches the Jaeger-LeCoultre for slenderness—it actually beats it, by over a third of a millimetre. Not much in real-world standards, but when you're talking about ultra-thin watches? It may as well be a mile.

This whisker of extra thinness must come at a cost—perhaps power reserve or beat rate or something like that, right? Not at all—there's 50 hours of power for the Zenith and just 43 for the Jaeger-LeCoultre, and both beat at a decent 28,800 vph. The killer blow is the price: Zenith's Ultra Thin offering is £3,600, while Jaeger-LeCoultre's tips the scales at £6,100—not too far off double.

The Zenith is thinner than the Jaeger-LeCoultre by a third of a millimetre

Is that the death knell for the Jaeger-LeCoultre? On the face of it, it seems so, but take a second, more critical look and the price difference starts to make more sense. Most obvious is the solid gold rotor weight in the Jaeger-LeCoultre, and then the heat-blued screws. The free-sprung balance with its adjustable screwed weights is harder to set up, but more stable than the regulated balance in the Zenith once it is. And then there's the details you can't see, like the ceramic ball-bearing mechanism in the rotor weight that requires no lubrication or maintenance at all.

Zenith is a world-class watchmaker, that's for certain, but it's details like these that makes Jaeger-LeCoultre a world-class watchmaker and engineer.

The in-house Elite movement has 50 hours of power reserve

What an immense privilege it is that these two masterful creations exist to choose from. If an ultra-thin dress watch is something you're considering, the dilemma they collectively present is something to be savoured, a chance to really get to grips with the nuances of each watch. It's a difficult decision, no doubt about it, but one we'd all enjoy having the opportunity to make.

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