A self-correcting masterpiece
Whether the date is shown by digits in a window or by a hand pointing to a scale, a date display surely ranks among the most important additional functions of mechanical and electronic watches. But the industry’s typical date displays share one weakness: they only track the date correctly for maximally 92 consecutive days each year, from July 1 to September 30. Manual resetting is needed at the end of February, April, June, September, and November. But this is unnecessary if a calendar module is installed below the dial like the mechanism in A. Lange & Söhne’s 1815 Annual Calendar. Mounted on the dial side of Caliber L051.3, this intelligent module “knows” the length of each month from March to January. And it remembers this in an especially slim and horologically elegant guise. All this mechanism needs to depict the date, day of the week, month, and lunar phase requires a mere 1.4 millimeters of headroom. The moon-phase display errs by one full day only after 122.6 years have passed. Despite its impressive outer and inner virtues, this masterpiece of Saxon watchmaking might occasionally be left to languish inside a safe. The spring barrel supplies energy for approximately 1.5 million semi-oscillations of the variable inertia balance, or in other words 72 hours. If left to wind down this watch’s displays will need manual attention. To simplify this task, the designers equipped their opus with several corrector buttons. Pressing the visible button at 2 o’clock on the case flank causes all of the indicators to advance simultaneously. This button’s three inset companions facilitate individual corrections of the day of the week, month, and moon phase. Additionally, A. Lange & Söhne premieres another inset corrector button here, which solely moves the date display. User- friendliness is accordingly prioritized in this 40 mm white gold wristwatch. A point of honor is the trans- parent case back, through which aficionados can admire all of the hand-wound movement’s handsome details, such as the ratchet and crown wheels embedded in the spacious nickel silver three-quarter plate.
1815 Annual CalendarThe calendar requires manual adjustment only once per year and the moon-phase display won’t err by one full day until 122.6 years have passed: together, they comprise an attractive and useful horological complication.
- Material: 18 k white gold
- Caliber: Hand-wound, Caliber L051.3
- Diameter: 40 mm
- Special features: Annual calendar with hands to indicate the date, the day of the week and the month, moon-phase display
- Wempe reference: LA200033