Even before you consider the limited-edition appeal of this piece, the “regular” 1815 Tourbillon sets a high standard in terms of its horological content. When it was presented four years ago, this tourbillon combined two patented developments by A. Lange & Söhne for the first time on a tourbillon: the zero-reset mechanism and the stop seconds mechanism.
The zero-reset mechanism was patented by A. Lange & Söhne in 2000 and mimics the operation of a chronograph reset function in a non-chronograph watch, stopping the balance wheel before returning the seconds hand to the 12 o’clock position. This is designed to allow the time to be set to the nearest second and makes sense for a timepiece that is designed around optimum precision. After all, why have a tourbillon designed to compensate the adverse effects of gravity if you are not going to bother to set it precisely in the first place? Stopping the balance wheel in a tourbillon, however, is slightly more complicated, because the balance wheel is oscillating inside a tourbillon carriage that is rotating about its own axis once every minute. There is therefore a risk that the spring that is supposed to make contact with the balance wheel when the crown is pulled out could instead hit one of the three pillars of the revolving tourbillon carriage. The movement designers at A. Lange & Söhne neatly obviate this risk by using a Y-shaped spring, so that if one of its arms comes into contact with one of the tourbillon carriage pillars, the other one is guaranteed to touch, and therefore stop, the balance wheel.
That the 1815 Tourbillon is now available as a very limited series with an enamel dial (unusually on a copper, rather than gold, base) adds a further touch of superiority to an already sublime timepiece, as does the diamond endstone in a screwed gold chaton on the fourth-wheel bridge and the red 12 in the appropriate place on the dial, which adds an extra layer of complexity to the enamelling process. Since A. Lange & Söhne watches come almost exclusively with precious metal cases, the limited-edition 1815 Tourbillon uses the most precious of them all, platinum, for its 39.5mm diameter case.
The manually wound Lange manufacture calibre L102.1 is visible through a transparent sapphire crystal case back that shows off the wonderful decoration on the movement that is carried out by hand at the company’s workshops in Glashütte (note the “freehand” engraving on the fourth-wheel bridge). To make matters even worse for the decorators, the plates and bridges are made of untreated German silver, meaning that the slightest trace of contact with a wayward and unprotected fingertip could consign the movement, and the many hours of work spent on it, straight to the recycling bin. The key component of the watch, the balance spring, is manufactured in-house at the company’s workshops in Glashütte, giving A. Lange & Söhne complete control over the accuracy of its movements.
The fortunate 100 owners of this limited-edition 1815 Tourbillon can rest assured that its blue steel hands will show the correct time for at least 72 hours each time that the manually wound movement is rewound and strapped to the wrist with the hand-stitched alligator leather strap.
