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The Encyclopedia of Horology

Pocket watch · Perpetual calendar pocket watch

Audemars Piguet Ref. 5559 Skeletonized Perpetual Calendar Pocket Watch

Partially verified

This Audemars Piguet Ref. 5559 is an 18K yellow gold, skeletonized pocket watch featuring a perpetual calendar and moon phase display. Originally sold in September 1985, the watch is constructed with a three-body, polished gold case protected by sapphire crystals. The dial design incorporates an outer chapter ring with painted black Roman numerals, an inner minute track, and four subsidiary dials managing the calendar functions, including months, leap year cycle, days of the week, date, and moon phase age. It is powered by the gilt, hand-engraved Caliber 502 movement, which is equipped with 20 jewels, a straight-line lever escapement, a monometallic compensation balance, and a self-compensating blued steel Breguet balance spring. The watch is complemented by blued steel cathedral hands and remains signed on the dial, case, and movement. The ensemble includes two certificates of origin, a leather pouch, and a green leather folder.

Front view of the Audemars Piguet Ref. 5559 pocket watch showing the skeletonized movement, perpetual calendar subsidiary dials, and moon phase aperture.
Front view of the Audemars Piguet Ref. 5559 pocket watch showing the skeletonized movement, perpetual calendar subsidiary dials, and moon phase aperture. — Antiquorum. Rights pending — permission not yet requested. Original source

Catalogue identity

Source
catalog.antiquorum.swiss
Category
Pocket watch · Perpetual calendar pocket watch
Maker / attribution
Audemars Piguet
Reference
5559
Catalogue / lot identifier
241
Source-reported date
1985
Source-reported place
Not established
Source-reported serial
B78865

Source-reported attribution and specifications are not independent authentication. A listing does not establish present ownership, current display, availability or permission to reproduce.

Object description

Case and Dial

The timepiece is housed in a three-body, solid 18K yellow gold case featuring a polished finish. The design relies on sapphire crystals to provide visibility into the skeletonized interior.

The dial is an integral part of the skeletonized display, featuring painted black Roman numerals positioned on an outer chapter ring. It includes an inner minute track and four distinct subsidiary dials that indicate the months, four-year leap year cycle, days of the week, and calendar date. A specific aperture for moon phases and the age of the moon is also present. Blued steel cathedral hands are used to track the time.

Evidence for this section
  • “Three-body, solid, polished, sapphire crystals.”
  • “Skeleton with painted black roman numerals on the outer chapter ring”
  • “Blued steel cathedral hands.”

Movement and Escapement

At the heart of the watch is the Caliber 502, a gilt movement that is fully hand-engraved to match the skeletonized aesthetic. The movement functions using 20 jewels.

The technical architecture of the movement includes a straight-line lever escapement. Timekeeping stability is managed by a monometallic compensation balance paired with a self-compensating blued steel Breguet balance spring. The auction description reports that the movement requires an overhaul.

Evidence for this section
  • “Cal. 502, gilt, hand-engraved, 20 jewels, straight line lever escapement”
  • “monometallic compensation balance, self-compensating blued steel Breguet balance spring.”
  • “Overhaul recommended, at buyer's expense”

Provenance and Documentation

The watch is identified by movement number 263701 and case number B78865. Documentation indicates the piece was originally sold in September 1985. The auction house notes the watch was previously in the possession of an original Japanese owner.

Accompanying the watch is a comprehensive set of accessories. This includes two official certificates of origin, a protective leather pouch, and a green leather folder containing various related leaflets.

Evidence for this section
  • “Sold in September 1985.”
  • “Accompanied by two certificates of origin, leather pouch, green leather folder with various leaflets”
  • “Property of the Original Japanese Owner”

Open research questions

  • What specific production number of the Ref. 5559 series does case B78865 represent?
  • Does the 'hand-engraved' finishing on the Caliber 502 follow a standardized pattern for all skeletonized versions of this reference?

Source evidence

Recorded claims and source quotations for Audemars Piguet Ref. 5559 Skeletonized Perpetual Calendar Pocket Watch
FieldSource-reported valueSource quotation
MakerAudemars Piguet“Audemars Piguet”
Movement Number263701“movement No. 263701”
Case NumberB78865“case No. B78865”
Sold DateSeptember 1985“Sold in September 1985”
Caliber502“Cal. 502”
Diameter49 mm“DIAM. 49 mm”
Jewels20“20 jewels”

Visible details

  • Painted black Roman numeral hour markers on the chapter ring
  • Blued steel cathedral-style hands
  • Moon phase aperture featuring the Audemars Piguet signature
  • Exposed, hand-engraved gilt movement plates

Research qualifications

  • The auction description recommends a mechanical overhaul for the movement.
  • The case condition is graded as slightly scratched.

Photograph identity and source facts were screened before import; rights clearance remains pending.

Consulted source

AUDEMARS PIGUET REF. 5559 SKELETONISED PERPETUAL CALENDAR DRESS WATCH YELLOW GOLD Audemars Piguet, movement No. 263701, case No. B78865, Ref. 5559. Sold in September 1985. Very fine and rare, elegant and thin, skeletonized 18K yellow gold pocket watch with perpetual calendar and moon phases. Accompanied by two certificates of origin, leather pouch, green leather folder with various leaflets

Reviewed 2026-10-26 · Record a7fa40ce93

Terms in this record

Glossary explanations for terms named in this object’s record.

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