Day, date month... Gear wheels, adjustments, energy... Because running such an elaborate complication as a calendar within a classic watch naturally has a detrimental effect on the precision of the time indications, the watchmakers at Jaeger-LeCoultre knew they had found in the Dual-Wing concept an instrument capable of creating a perfect alchemy: a calendar watch that was as accurate as a chronometer.

Arranged on the elegant and easily readable dial, the hours, minutes, seconds and moon-phase displays appear to make the Duomètre à Quantième Lunaire a classic watch model. But inside the case and partially hidden from view beats Calibre 381, a prodigious movement boasting unprecedented precision based on the Dual-Wing concept and which propels the watch firmly into the spheres of Haute Horlogerie.

The truly extraordinary appearance of the watch lies in the actual concept behind the Dual- Wing movement, which is distinguished by the presence of two independent energy sources: the first, regulated by the escapement and the balance, is entirely dedicated to the precise measurement of the passing of time; whereas the second source of energy is devoted to the display of the functions: hours, minutes, seconds, calendar and moon phases for both hemispheres. Their synchronisation is ensured by the jumping seconds hand mechanism.

This Duomètre à Quantième Lunaire brilliantly illustrates the extreme research undertaken in the laboratory-workshops of Jaeger-LeCoultre: this watch reaches the heights of precision with a jumping seconds hand moving in sixth of a second increments while displaying the date and the moon phase on a separate sundial.

Through in-depth study and a willingness to challenge the fundamental principles of horological theory, the Jaeger-LeCoultre specialists have succeeded in creating a calendar watch in accordance with the Dual-Wing concept – a principle featuring exceptional characteristics that enable a degree of rating precision that was previously the exclusive preserve of timepieces free of any complications.

Only the expertise accumulated over 178 years could thus enable Jaeger-LeCoultre to begin writing a new chapter in the history of Fine Watchmaking...