Nominated for the “Innovation Watch” watch award at the 2013 Grand Prix d’Horlogerie de Genève, Girard Perregaux’s latest horological marvel, the Constant Escapement, is a force to be reckoned with.

Having first teased the public during the SIHH show of 2008 with a prototype of the movement, it has taken Girard Perregaux 5 years (and all the investments that entails; financial and otherwise) to make this micromechanical breakthrough a reality.

Let’s talk a little about constant force: in a standard mechanical watch movement with a traditional Swiss lever escapement, the balance wheel oscillates with a higher amplitude when fully wound, then gradually dwindles down as the mainspring uncoils and the power reserve diminishes. This means that the energy provided to the balance wheel throughout the wind cycle is erratic and variable; consequently resulting in not-so-accurate chronometry. In other words, the force provided to the regulatory organ isn’t constant.

Several watch manufactures have attempted to remedy this with their own “constant force” movements, like the FP Journe “Remontoir d’Egalité” or the more recent Romain Gauthier “Logical One”. While these do provide a more consistent force to the balance wheel, it’s not exactly constant force as the energy transferred to the balance wheel throughout the wind cycle is still variable.

This is where the Girard Perregaux Constant Escapement stands out. Unlike the aforementioned watches where the force is regulated via the barrels and mainspring, the Constant Escapement, as the name would imply, takes it to the escapement itself.

See what they’ve done here? Girard Perregaux have designed an escapement with an intermediary device between the balance and escape wheels. Thanks to advancements in silicon technology and manufacturing techniques, the intermediary device uses a “buckling” action from a 14-micron silicon blade (that’s 6x thinner than a human hair!) that acts as an energy storage unit, compensating for the variable output of energy from the mainspring by giving constant impulses to the balance wheel.

The best way to visualize it would be the same way its inventor Nicolas Dehon first got the idea. If you were to take a train ticket (that’s what he did) or playing card between your thumb and forefinger and bend it to form a “C”, then push the arched side, you would feel resistance until it eventually “fails” and snaps to the opposite side in a mirrored position, supplying force is it does so.

This is how the silicon blade works. It pushes the balance wheel forward and compensates for the variable energy of the barrel while simultaneously liberating that exact amount of energy before the process starts again. This means that regardless of the power reserve, the watch will run at a constant rate.

Because of this buckling mathematical failure system, two escape wheels are used to work in tandem. The escape wheels have only 3 teeth each, allowing them to run at a frequency of 3Hz.

But as if this revolutionary escapement wasn’t enough, Girard Perregaux included a few other goodies. The barrels, using a newly developed and patented construction where the cover and ratchet are made of a single component, provide a power reserve of approximately 7 days. The double twin barrels are coupled in parallel, another patent-pending feature of the Constant Escapement. The combined four barrel springs measure a total of 3 meters in length.

The watch itself is a bit of a departure for Girard Perregaux, but I wouldn’t say totally unexpected. In recent years, GP have brought out some complicated pieces with a modern air to them, like the Bi-Axial Tourbillon in Tantalum. The Constant Escapement comes in a 48mm white gold case, complete with a circular brushed bezel and polished case. Some may find the 48mm case overwhelming, but I don’t think GP chose to make a big watch simply because they felt like it. The Constant Escapement movement is pretty big, and as is often the case with new movement designs, you need a bigger case to accommodate all that groundbreaking technology. I only managed to take wrist shots with my cell-phone so I won’t be sharing those. Suffice to say that I found the Constant Escapement easy to wear thanks to the short lugs and curved strap ends.

The dial is split into two parts, with the bottom half reserved entirely for the visible Constant Escapement. The top portion is a bit more familiar, with an off-centered two-hand dial and a linear power reserve.

The movement is given a more “concept watch” look with a dark galvanic treatment (probably rhodium and/or ruthenium galvanic plating) and an overall frosted matte finish. The angling of the bridges is excellently done, and I love how they’ve incorporated their iconic “triple bridge” design into the Constant Escapement.

Girard Perregaux have achieved what many watchmakers have dreamt of and produced the first true “constant force” watch movement. I have no doubt that Girard Perregaux will use this technology in other watches, but this first edition of the Constant Escapement will go down in watchmaking history as a world first.

The Constant Escapement comes at a price of 124’200 CHF, which is quite fair considering just how intricate and groundbreaking the watch really is.

More information at www.girardperregaux.com