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The Encyclopedia of Horology

Wristwatch · Perpetual calendar chronograph

Patek Philippe Perpetual Calendar Chronograph Reference 3970EP

Partially verified

This Patek Philippe reference 3970EP is a second-series perpetual calendar chronograph wristwatch. The watch features a 36mm platinum case manufactured by Ateliers Réunis, characterized by the inclusion of a "small hallmark." The watch is powered by the manual-wind caliber CH 27-70 Q, which is based on an ébauche from Lemania. The dial is the "Argenté" silver-toned version associated with early production runs, featuring "American Typewriter" typography and leaf-shaped ("feuille") hands. The perpetual calendar mechanism incorporates indicators for the day, date, month, leap year, and moon phase, alongside a 24-hour display. This reference was introduced in 1986 as the successor to the reference 2499. According to the provided source, this specific iteration in platinum was produced in a limited quantity of 11 units. The object is reported to be in well-preserved condition.

Front view of the Patek Philippe reference 3970EP wristwatch, showing the dial details, pushers, and original paperwork.
Front view of the Patek Philippe reference 3970EP wristwatch, showing the dial details, pushers, and original paperwork. — Zamanito. Rights pending — permission not yet requested. Original source

Catalogue identity

Source
zamanito.com
Category
Wristwatch · Perpetual calendar chronograph
Maker / attribution
Patek Philippe
Reference
3970EP
Catalogue / lot identifier
Source URL identifies the listing
Source-reported date
circa 1986
Source-reported place
Switzerland

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 Design

The watch is housed in a 36mm platinum case, which the source notes is a rare material for this reference. The case was manufactured by the specialist workshop Ateliers Réunis and bears a small hallmark. The aesthetic follows the design language of the second series of the 3970 line, which transitioned away from earlier configurations.

The dial is rendered in a warm silver tone, known as Argenté. The layout includes specific typography for the calendar and chronograph indications, utilizing the American Typewriter font.

Evidence for this section
  • “بدنه این ساعت با قطر ۳۶ میلی‌متر توسط کارگاه مشهور Ateliers Réunis ساخته شده و ویژگی متمایز «نشان کوچک» (Small Hallmark) را داراست”
  • “صفحه این ساعت از نوع نقره‌ای گرم‌تر (Argenté) ویژه سری‌های اولیه بوده و فونت نگارش آن از نوع «American Typewriter» است”

Movement and Functionality

At the heart of the reference 3970EP is the caliber CH 27-70 Q. This movement functions as a perpetual calendar chronograph, a complex combination of complications that includes moon phase tracking and a 24-hour subdial. The movement is developed on an ébauche provided by Lemania, a standard arrangement for this reference within the Patek Philippe catalog of the era.

The movement manages the chronological and perpetual calendar data, which is presented on the dial through a series of sub-registers. The layout is designed to maintain legibility despite the density of information provided by the perpetual calendar functions, which include the date, month, day, and leap year cycles.

Evidence for this section
  • “در بخش موتور، از کالیبر CH 27-70 Q استفاده شده که بر پایه ابوش (ébauche) لمانیا (Lemania) توسعه یافته است”

Historical Context and Condition

The reference 3970 was introduced by Patek Philippe in 1986 as the successor to the reference 2499. While the case dimensions are smaller than its predecessor, the movement offers increased technical density and complexity.

The auction description reports that the watch is in a well-preserved state. However, the documentation does not include specific details regarding the watch's service history or long-term operational performance. The rarity of the platinum configuration is emphasized, with the source stating that only 11 units were produced in this metal for the second series.

Evidence for this section
  • “مدل ۳۹۷۰ در سال ۱۹۸۶ جانشین رفرنس افسانه‌ای ۲۴۹۹ شد”
  • “وضعیت فیزیکی این ساعت در وضعیت بسیار خوبی حفظ و نگهداری شده است (Well-preserved)”
  • “تنها ۱۱ نمونه از سری دوم این رفرنس در قالب پلاتین به تولید رسیده است”

Open research questions

  • Can the 'small hallmark' placement be verified against internal factory records?
  • Does the serial number on the movement align with the projected production date of 1986?

Source evidence

Recorded claims and source quotations for Patek Philippe Perpetual Calendar Chronograph Reference 3970EP
FieldSource-reported valueSource quotation
MakerPatek Philippe“Patek Philippe”
Reference3970EP“3970EP”
Case MaterialPlatinum“قاب پلاتینی”
Case Diameter36 mm“۳۶ میلی‌متر”
Movement BaseLemania“Lemania”
Production SeriesSecond Series“سری دوم”
Case MakerAteliers Réunis“Ateliers Réunis”
ComplicationsChronograph, perpetual calendar, moonphase, 24-hour indicator“کرنوگراف، تقویم دائمی، فاز ماه (Moonphase)، نشانگر ۲۴ ساعته”

Visible details

  • Silver-toned dial with three subdials
  • Three rectangular chronograph pushers and a crown on the right side of the case
  • Dark blue strap with visible stitching
  • Moon phase display at the six o'clock position

Research qualifications

  • Total production of 11 platinum units is reported based on external sources rather than manufacturer archives
  • Specific maintenance history is not documented by the seller

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

Consulted source

ساعت مچی Patek Philippe رفرنس 3970EP سری دوم تقویم دائمی کرنوگراف

Reviewed 2026-11-02 · Record 682f08ba83

Terms in this record

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

Other perpetual calendar chronograph records