A. Lange & Söhne 1815 Tourbillon

A. Lange & Söhne introduced the 1815 Tourbillon at SIHH 2014. It is an inventive watch: besides the tourbillon it has a stop mechanism and a zero-reset for the tourbillon and small seconds. Part of the mechanism can be seen through the open small seconds.

Stopping a tourbillon

For a long time it was impossible to set a tourbillon watch exactly, because the tourbillon could not be stopped. In 2008 Lange’s calibre designers solved the problem by braking the balance directly inside the rotating cage. When the crown is pulled, a lever mechanism presses a movable V-shaped spring onto the balance wheel and stops it instantly.

The 1815 Tourbillon uses this patented mechanism, partly visible through the aperture in the dial, and pairs it with the patented zero-reset. When the crown is pulled, the blued-steel small seconds hand jumps to zero. The minute hand can then be placed exactly on a minute stroke and the watch started with one-second accuracy.

Design and movement

The restrained design favours legibility and follows the ideals of Ferdinand A. Lange, whose birth year gives the watch its name. The tourbillon behind the dial aperture is the only sign of the complication. Its diameter, 13.2 millimetres, is almost a millimetre larger than in earlier versions, and its arbor carries the small seconds hand, in blued steel for contrast against the light dial. Arabic numerals and a railway-track minute scale recall historic Lange pocket watches.

Balance wheel and hairspring are made in-house and matched to each other, and the tourbillon carries a diamond endstone. The case, 39.5 millimetres in diameter, is in pink gold or platinum, and the platinum version is limited to 100 watches. It was the first Lange tourbillon watch with stop seconds and zero-reset.