The LANGE 1 TOURBILLON PERPETUAL CALENDAR combines two classic complications with the iconic design of A. Lange & Söhne’s most famous watch family. Configured around the time indication, the calendar displays and the peripheral month ring deliver full time and date readings at a single glance. All of the perpetual calendar displays advance instantaneously. Thus, the date, day of the week, month, leap year, and moon phase can never be interpreted incorrectly. The mechanism is designed in such a way that it must be advanced only by one day in the year 2100. And the moon-phase display will even run true for 122.6 years before it needs to be corrected by one day.

Despite the wealth of information it delivers, the dial is so well organised that many a second look is required to recognise fully the technical complexity of this horological magnum opus. Only a modest inscription beneath the 12 refers to the existence of the tourbillon. But a glance through the sapphire-crystal caseback reveals its technical ingenuity. The patented stop-seconds mechanism instantaneously brings the balance inside the tourbillon cage to a standstill when the crown is pulled.

1823 ALS L082

This allows the watch to be set with one-second accuracy. The upper part of the tourbillon cage is decorated with black polish, no doubt the most sophisticated and time-consuming type of artisanal finissage. The bearing of the tourbillon cage features a diamond endstone as a reminiscence of the historic 1A pocket watches of the venerable A. Lange & Söhne brand.

A massive central rotor with a 21-carat gold segment in the middle efficiently tensions the mainspring of the self-winding calibre L082.1 movement. The platinum centrifugal mass on the periphery of the rotor delivers extra torque so that the maximum power reserve of 50 hours is built up after just a short time on the wrist. Typical Lange quality hallmarks include the lavishly decorated movement with hand-engraved tourbillon and intermediate-wheel cocks as well as six screwed gold chatons.