The power reserve indicator, termed Reserve de Marche in French, is a useful complication of the watch that is similar to that of a car’s fuel gauge.
As its names implies, it shows you how much energy the mainspring of the watch is holding.
Not only is the feature good for telling you when the watch needs winding but you can also use it to tell if the mechanism is working as it should.
For example, if your watch has a power reserve of 42 hours but stops well short of that, it is a clear sign that it needs attention.
Watches with the power reserve complication are more common nowadays – but not to the point that they become less treasured.
In fact, the power reserve indicator of certain watches has been employed by watchmakers to show off their prowess in creating movements with longer-than-average power reserve.
A power reserve of seven, eight, 10 and even 31 days is now possible.
The International Watch Company (IWC), the famous watchmaker from Schaffhausen, Switzerland is well loved by many watch aficionados, and their Pilot’s Watch range has reached iconic status worldwide.
None more so than the Big Pilot Watch, whose 46.2mm case, riveted crocodile leather strap, fluted cone-shape crown, and seven days’ power reserve combine to make it handsome yet highly functional.
Andreas Boesch is a Big Pilot’s Watch fan. And who can blame him?
Lest you think he only has eyes for IWC, think again. While tapping his knowledge, we found out that he loves many different kinds of watches – even a clock from another famous Richemont-owned brand.
TORQUE: Can you tell us more about the movement in the Big Pilot and the Big Ingenieur?
BOESCH: Both are equipped with our in-house movement, the Calibre 5000. It generates a power reserve of seven days, when the rotor completes 1,960 full revolutions.
Actually, the power reserve is longer – 8.5 days, to be precise.
But this would have made it more prone to inaccuracies, so our watchmakers decided to stop the movement after seven days with an ingenious little mechanism.
The power reserve complication can only be found in the Pilot, Portuguese and Ingenieur ranges. Is there a reason for this?
The Calibre 5000 is an extra-large movement, with a diameter of 37.8mm and a height of 7.2mm. A large movement such as this requires an equally large-size case.
When you look into our history, you will see that the first Portuguese was equipped with a large pocket watch movement. The original Big Pilot’s Watch had an impressive diameter of 56mm.
As for the Ingenieur, we felt that we had to offer an extra-large Ingenieur, which was aptly named “Jumbo” because of its size.
Difficult question next: Besides IWC watches, do you have another favourite watch brand?
I’ve always admired Ulysse Nardin for their Astrolabium and Jaeger-LeCoultre for their Atmos.
Can you imagine the sky on a wristwatch or a clock, which is powered by temperature changes?
Recently, I saw the Jaeger-LeCoultre Atmos from Marc Newson. What a beauty it is!
What are your favourite IWC watches and why?
I love to change watches based on my mood or for different occasions. Last week, I wore the IWC Big Pilot’s Watch.
Over the weekend, I had an IWC Aquatimer with rubber strap, which is very practical if you do outdoor sports.
And, currently, I’m waiting for the IWC Portuguese Vintage for more formal occasions because it’s so classic and elegant.
Last but not least, any advice for watch collectors looking to buy a watch with the power reserve complication?
Simple – please consider IWC.
