The Vacheron Constantin Traditionnelle Complete Calendar Openface Ref. 4020T/000R-B654 is a breathtaking fusion of classical Genevan watchmaking and contemporary architectural design, offering a captivating view of its mechanical heart through a unique, multi-layered openworked sapphire dial that reveals the intricate Calibre 2460 QCL/2 beneath, whose main plate and bridges are highlighted by a sophisticated anthracite NAC treatment . This striking 41mm 18K rose gold case, with its slim bezel and stepped flanks, measures 11.05mm in thickness and provides a warm, luxurious frame for the dial’s complex visual depth . The dial itself is a masterclass in layering: a slate grey opaline chapter ring displays the date numerals and a railroad minutes track, while the partially transparent construction allows full visibility of the sapphire day and month discs below the 12 o’clock position and the precision moon phase indicator at 6 o’clock, featuring a photo-realistic depiction of the moon against a smoked grey background . Powered by the in-house automatic Calibre 2460 QCL/2, this movement comprises 312 meticulously finished parts, beats at a frequency of 28,800 vibrations per hour, and delivers a 40-hour power reserve . The exquisite finishing, worthy of the prestigious Hallmark of Geneva, includes Geneva striping on the bridges and perlage on the baseplate, all visible through the sapphire crystal caseback, which also showcases the 22K rose gold rotor with a skeletonized Maltese cross design . The watch is secured by a luxurious grey alligator leather strap with a matching 18K rose gold pin buckle, and offers a water resistance of 30 meters (3 bar) . This timepiece represents the perfect harmony of Vacheron Constantin’s centuries-old heritage and a modern, openworked aesthetic, appealing to connoisseurs who seek both horological substance and visual artistry. Key specifications: 41mm 18K rose gold case; openworked sapphire dial with slate grey opaline chapter ring; in-house automatic Caliber 2460 QCL/2 with complete calendar (day, date, month) and precision moon phase; 40-hour power reserve; grey alligator strap with 18K rose gold pin buckle; 30m water resistance; sapphire crystal front and back; Hallmark of Geneva certified .