The sky measured to perfection
Excalibur Biretrograde Perpetual Calendar
The Excalibur Biretrograde Perpetual Calendar is a timepiece that distils the most demanding traditions of Geneva watchmaking into 40 mm of pink gold. Its perpetual calendar, automatically accounting for months of 28, 30, and 31 days without manual correction, is expressed through a biretrograde display that brings mechanical poetry to the reading of time. An astronomical Moonphase, accurate to within one day over 122 years, completes the celestial portrait. Open-worked and structured in three dimensions, the dial transforms these classical complications into something resolutely present.
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Case
Pink gold 750/1000 case with open case back
- Water Resistance:
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Dial
The dial features a multi-layered design, showcasing varnished mother-of-pearl, pink gold accents, flange with PVD and satin finishes, and a blue aventurine moon phase disc with engraved pink gold moons.
- Main material: Pink Gold 18K
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Strap
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Clasp
Pink gold 750/1000, triple folding buckle interchangeable with Quick Release System - QRS
- Type: Pink Gold 18K
A complication born from the founder's obsession
Roger Dubuis spent decades devoted to a specific conviction: that complications should serve legibility. The perpetual calendar was among his most cherished pursuits, a mechanism that mirrors the irregular rhythms of the astronomical year, faithfully and without interruption. This timepiece carries that conviction forward. The biretrograde indication, where the hands sweep elegantly across an arc before snapping back to their origin, transforms the act of reading the date and day into something deliberate and alive.
A new generation of perpetual calendar movement
Calibre RD850
At the heart of this timepiece beats the RD850, a new-generation biretrograde perpetual calendar calibre developed entirely in-house. Its perpetual calendar module operates on a cam-and-lever system that reads the length of each month and advances accordingly, requiring no correction until year 2100. The biretrograde complication adds another layer of mechanical sophistication: two spring-loaded hands retract instantaneously at the end of their arc, a mechanism that demands precise tension control and tolerances measured in microns. The movement bears the Poinçon de Genève, attesting to the quality of its 56 individual decorative and technical criteria, including inner-anglage finishing on components invisible to the naked eye.
122 years before the first adjustment
The astronomical moonphase
Positioned at 6 o'clock, the astronomical Moonphase of the RD850 follows the Moon's orbital cycle around the Earth with a precision rarely achieved in mechanical watchmaking. Calibrated to 29 days, 12 hours, and 45 minutes, the true duration of one lunar cycle, it displays the waxing and waning of the Moon as it appears in the sky, with a deviation of just one day over 122 years. The disc itself is crafted in aventurine, set with a domed 18K pink gold moon that is laser-engraved for depth and texture. The Moonphase counter is framed in Astral Blue mother-of-pearl, drawing the eye downward through the open-worked architecture to the most quietly spectacular detail on the dial.
Architecture in three dimensions
Dial & case
The dial of the Excalibur Biretrograde Perpetual Calendar is conceived as a layered landscape. Constructed across multiple planes, it reveals the movement beneath while imposing its own structural logic: bridges, apertures, and subdials arranged with deliberate asymmetry. The astral blue tones, deepened by mother-of-pearl accents, evoke the night sky that inspired the Timepiece's complications. The 40 mm pink gold case balances presence with wearability, its polished and satin-brushed surfaces alternating to catch and hold the light. The whole is finished with inner-angle polishing achievable only by hand, a detail felt rather than seen.
“This is a watch of today, inspired but not restricted to the past, projected into a future that belongs to us.”
Details Defined
The Signature
Case
Distinctive triple-lug case with sculpted, geometric lines
Bezel
Graphic fluting, sharp and precise like a sword strike
Ecliptic segments
Mother-of-pearl and signature
Moonphase
Made with blue aventurine and curved 18K yellow gold
Hands
Intricately crafted 18K gold skeleton hands
Crown
Crafted for comfort: multi-component crown
Flange
Double-sided flange, a maison’s seal
Oscillating weight
Historical design-inspired oscillating weight
Bi Retrograde Perpetual Calendar Moon Phase
RD850
RD850 caliber. Perpetual calendar with day, date, month and leap year with biretrograde display. Automatic, self-winding with pink gold rotor
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MOVEMENT
- Energy: Automatic, self-winding
- Power reserve: 60 Hours
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Decor
Côte de Genève, wheel-beveling, tool-beveling, burnishing, circular-graining, truing, external drawing, internal drawing, rounding, perlage, tip polish, mirror polish, teeth polish, inner wing beveling, inner angles, shot-blasting
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Technical Details
- Number of pieces: 438
- Number of rubis: 40
- Diameter: 14 3/4
- Frequency: 28800 Frequency (vph)
