Audemars Piguet Code 11.59 Ultra-Complication Universelle RD#4 White Gold — Skeleton Dial | Ref. 26398BC.OO.D002CR.02

Released in 2023 as one of the most technically ambitious horological objects of the decade, the Code 11.59 Ultra-Complication Universelle RD#4, ref. 26398BC.OO.D002CR.02, represents the absolute summit of Audemars Piguet's manufacture capability. Contained within a 42 mm 18-carat white gold round case — Code 11.59's own architectural statement of double-curved sapphire crystal and cushion-shaped middle — the RD#4 movement is an extraordinary integration of complications that includes a perpetual calendar, minute repeater, flying tourbillon, and a star wheel moon phase display, all delivered through a calibre of unprecedented engineering density.

Calibre 1000, which powers this piece, was developed entirely in-house and required years of engineering research to integrate its high-complication functions without sacrificing legibility or serviceability. The skeletonised dial reveals the RD#4's architecture in its full spatial complexity — gears, springs, and levers coexisting in a composition that is equal parts mechanism and three-dimensional artwork. The minute repeater's acoustic performance — its cathedral gongs tuned to produce a resonant, projecting sound from the white gold case — is a benchmark in contemporary grande sonnerie construction.

The Code 11.59 case format, with its round bezel transitioning through a tonneau-shaped middle to an octagonal caseback, was conceived as a deliberately original vessel distinct from the Royal Oak's legacy. Here, in white gold on a cream alligator strap with AP folding clasp, it provides a fittingly rarefied housing for watchmaking's most demanding achievement. Complete with box and papers, this is among the rarest and most consequential timepieces available to the serious collector today.