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The Encyclopedia of Horology

Wristwatch · Perpetual calendar

Patek Philippe Perpetual Calendar reference 3940J

Partially verified

This Patek Philippe reference 3940J is an 18k yellow gold perpetual calendar wristwatch dating to 1987. It represents an early second-series configuration, distinguished by a specific dial layout. This dial features sub-dials for day and month with double-step bevelled edges, while the subsidiary seconds dial at 3 o’clock excludes the crosshair markings found on later versions. The calendar displays are in French. The watch is powered by the ultra-thin automatic calibre 240Q movement and is encased in a 36mm yellow gold case with a solid case-back. The object is accompanied by an official Extract from the Archives confirming its manufacture and sale in 1987, as well as 2020 Patek Philippe service documentation. It is fitted with a leather strap and the original gold pin buckle.

Front view of the Patek Philippe 3940J showing the dial details, perpetual calendar sub-dials, and leather strap.
Front view of the Patek Philippe 3940J showing the dial details, perpetual calendar sub-dials, and leather strap. — Bulang & Sons. Rights pending — permission not yet requested. Original source

Catalogue identity

Source
www.bulangandsons.com
Category
Wristwatch · Perpetual calendar
Maker / attribution
Patek Philippe
Reference
3940J
Catalogue / lot identifier
Source URL identifies the listing
Source-reported date
1987
Source-reported place
Switzerland
Source-reported serial
283xxxx

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

Design and Dial Characteristics

The reference 3940J features a 36mm case crafted from 18k yellow gold, fitted with a solid case-back. The watch displays a perpetual calendar layout with a moon phase and inscriptions in French. This specific example is identified by the vendor as an 'early second-series' variant, produced for a restricted timeframe between 1987 and 1989.

The dial layout contains subtle variations compared to later iterations of the reference. The day and month sub-dials exhibit double-step bevelled edges, which the source describes as providing added visual depth.

Evidence for this section
  • “The day and month sub-dials feature distinctive double-step bevelled edges”
  • “subsidiary seconds dial at 3 o’clock is notably free of the crosshair”
  • “calendar displays are in French”

Movement and Functionality

At the heart of the timepiece is the Patek Philippe calibre 240Q, an ultra-thin automatic movement developed for perpetual calendar complications.

The movement is housed within a 36mm case, maintaining a balance between technical complexity and wearability.

Evidence for this section
  • “the real star is beneath it: Patek Philippe’s calibre 240Q perpetual calendar movement”
  • “ultra-thin calibre 240Q allowed the brand to house a full perpetual calendar in a beautifully proportioned 36mm case”

Provenance and Documentation

The object is accompanied by official documentation, including an Extract from the Archives provided by Patek Philippe, which confirms both the manufacture and the sale date of the watch in 1987. Further records include service documentation from 2020. The watch retains its original Patek Philippe gold pin buckle, paired with a leather strap.

The vendor identifies the watch as having a serial number beginning with 283 and a movement serial number beginning with 770. These numbers corroborate the 1987 production date attributed to the watch.

Evidence for this section
  • “Patek Philippe archive extract stating manufacturing and sale in 1987”
  • “2020 Patek Philippe service invoice”
  • “Case serial 283xxxx/Movement serial 770xxx, dating to 1987”

Open research questions

  • What specific production volumes exist for this 3940 configuration beyond the estimated 800 units?
  • Are there distinct case-back engravings or internal markings unique to the 1987 production run of this reference?

Source evidence

Recorded claims and source quotations for Patek Philippe Perpetual Calendar reference 3940J
FieldSource-reported valueSource quotation
MakerPatek Philippe“Patek Philippe”
Reference3940J“reference 3940J”
Case Material18k yellow gold“18k yellow gold”
MovementCalibre 240Q“Patek Philippe’s calibre 240Q perpetual calendar movement”
Calendar LanguageFrench“calendar displays are in French”
Date of Manufacture1987“dating to 1987”
Case Diameter36mm“36mm yellow 18k yellow gold case”

Visible details

  • Dial sub-dials have double-step bevelled edges
  • Subsidiary seconds dial at 3 o'clock lacks a crosshair
  • Calendar inscriptions are in French
  • Movement is the automatic Calibre 240Q

Research qualifications

  • Total production numbers are based on belief rather than confirmed data
  • The exact serial number is partially obscured in the source

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

Consulted source

Patek Philippe Perpetual Calendar 3940J Early Second Series in 18k yellow gold with Box and Extract of the Archives

Reviewed 2026-11-02 · Record a1fb5e2974

Terms in this record

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

Other perpetual calendar records