Skip to content
The Encyclopedia of Horology

Wristwatch · Perpetual calendar chronograph wristwatch

Patek Philippe Ref. 3970 First Series Perpetual Calendar Chronograph

Partially verified

This Patek Philippe reference 3970 is an 18K yellow gold perpetual calendar chronograph wristwatch manufactured in 1986. According to the auction source, it represents the fifth example produced in the first series, featuring a 36mm snap-back case manufactured by Ateliers Réunis. The satin-brushed silver dial displays applied yellow gold rectangular indices, feuille hands, twin day and month apertures, leap-year and 24-hour indicators, and a moon phase display integrated with a date ring. The watch is powered by the manual-wind calibre CH 27-70 Q with 24 jewels and is fitted with a leather strap.

Front view of the Patek Philippe reference 3970 perpetual calendar chronograph wristwatch showing dial, gold case, and strap.
Front view of the Patek Philippe reference 3970 perpetual calendar chronograph wristwatch showing dial, gold case, and strap. — Phillips. Rights pending — permission not yet requested. Original source

Catalogue identity

Source
www.phillips.com
Category
Wristwatch · Perpetual calendar chronograph wristwatch
Maker / attribution
Patek Philippe
Reference
3970
Catalogue / lot identifier
87
Source-reported date
1986
Country
Switzerland
Source-reported serial
875’004

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

Series Identification and Case Construction

This Patek Philippe reference 3970 is documented by the auction house as a first-series perpetual calendar chronograph in an 18K yellow gold 36mm case. According to the cataloguing essay, the first series was produced between 1986 and 1988 exclusively in yellow gold, beginning with movement number 875’000 with approximately 100 examples produced. Bearing movement number 875’004, this piece is described by the cataloguer as the fifth example made in the series.

The yellow gold case displays stepped lugs, round pump pushers, and case-flank correction pushers. The auction cataloguing reports a snap-on case back bearing the casemaker key number 28 stamped on the inside, which the cataloguer attributes to casemaker Ateliers Réunis. Direct visual confirmation of the movement and internal case-back hallmarks is not possible from the provided single front-facing photograph.

Evidence for this section
  • “Features a snap back case, feuille hands and rectangular indexes. Only produced in yellow gold with an estimated 100 examples produced, starting with the movement number 875’000 (The present example is the fifth first series example with the movement number 875’004).”
  • “The casemaker key number 28 stamped on the inside case back indicates that the yellow gold case was made by Ateliers Réunis.”
  • “18K yellow gold case with stepped bezel, fluted crown bearing the Calatrava cross, round pump pushers, and case-flank correction pushers.”

Dial Configuration and Functions

Direct visual inspection shows a silver dial with applied yellow gold rectangular indices, feuille hands, and dual apertures below 12 o'clock displaying the day and month. The dial outer perimeter incorporates printed minute/second graduations.

Three subsidiary dials are positioned at 3, 6, and 9 o'clock: a 30-minute chronograph register with an integrated leap-year indicator at 3 o'clock, a date ring enclosing a moon phase aperture at 6 o'clock, and running seconds paired with a 24-hour display at 9 o'clock. The cataloguing essay notes these subsidiary dials are slightly darker than the silver dial plate.

Evidence for this section
  • “Silver dial with dual apertures for day and month below 12 o'clock.”
  • “Three subsidiary dials at 3, 6, and 9 o'clock displaying 30-minute register with leap-year cycle, date with moon phase aperture, and running seconds with 24-hour indication.”
  • “The gorgeous silver dial with the slightly darker sub-dials, sticker protected snap-on caseback, applied gold rectangular indexes and feuille hands further confirm it as a first series example.”

Movement Details and Archival Documentation

The lot details record the movement as the manual-wind calibre CH 27-70 Q with 24 jewels, catalogued under movement number 875’004 and case number 2’824’111. Because internal mechanism photographs are not provided, mechanical details and markings rest on the seller's cataloguing.

The watch is reported to be accompanied by a Patek Philippe Certificate of Origin dated 31 January 1987, a fitted presentation box with outer packaging, and an Extract from the Archives confirming manufacture in 1986 and sale on 3 February 1987. The cataloguing also specifies an 18K yellow gold Patek Philippe pin buckle fitted to the leather strap.

Evidence for this section
  • “Calibre Manual, cal. CH 27-70 Q, 24 jewels”
  • “Case No 2’824’111”
  • “Clasp/Buckle 18K yellow gold Patek Philippe pin buckle”
  • “Accompanied by Patek Philippe Certificate of Origin dated 31st January 1987, fitted presentation box and outer packaging. Further delivered with Patek Philippe Extract from the Archives confirming its date of manufacture in 1986 and its subsequent date of sale on 3rd February 1987.”

Open research questions

  • What specific hallmarks, serial numbers, and reference numbers are physically stamped on the interior of snap-back case 2’824’111?
  • Does direct examination of calibre CH 27-70 Q (serial 875’004) confirm the Geneva seal and movement caliber designations reported by the cataloguer?
  • What markings or retailer stamps, if any, appear on the Certificate of Origin dated 31 January 1987?

Source evidence

Recorded claims and source quotations for Patek Philippe Ref. 3970 First Series Perpetual Calendar Chronograph
FieldSource-reported valueSource quotation
Case Number2’824’111“Case No 2’824’111”
Movement CalibreManual, cal. CH 27-70 Q, 24 jewels“Calibre Manual, cal. CH 27-70 Q, 24 jewels”
Case Dimensions36mm diameter“Dimensions 36mm diameter”
Case Material18K yellow gold“Material 18K yellow gold”
CasemakerAteliers Réunis“The casemaker key number 28 stamped on the inside case back indicates that the yellow gold case was made by Ateliers Réunis.”
Buckle Type18K yellow gold Patek Philippe pin buckle“Clasp/Buckle 18K yellow gold Patek Philippe pin buckle”
Date of Sale3 February 1987“subsequent date of sale on 3rd February 1987”
Certificate of Origin Date31 January 1987“Accompanied by Patek Philippe Certificate of Origin dated 31st January 1987”

Visible details

  • Silver dial with dual apertures for day and month below 12 o'clock.
  • Three subsidiary dials at 3, 6, and 9 o'clock displaying 30-minute register with leap-year cycle, date with moon phase aperture, and running seconds with 24-hour indication.
  • 18K yellow gold case with stepped bezel, fluted crown bearing the Calatrava cross, round pump pushers, and case-flank correction pushers.
  • Fitted to a tan grained leather strap with matching contrast stitching.

Research qualifications

  • Movement and interior case back are not visible in the provided image.
  • Casemaker attribution to Ateliers Réunis relies on source reporting of the internal key number 28 hallmark.

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

Consulted source

Patek Philippe TOKI: Watch Auction

Reviewed 2026-10-21 · Record 98e95e1506

Terms in this record

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

Other perpetual calendar chronograph wristwatch records