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The Encyclopedia of Horology

Wristwatch · Dress watch

Patek Philippe Calatrava Ref 3520D

Partially verified

This Patek Philippe Calatrava reference 3520D is a dress watch featuring an 18k white gold 32mm case with a Clous de Paris hobnail bezel and a screw-down caseback. The watch is powered by the ultra-thin, manually wound Patek Philippe calibre 175 movement. The dial is finished in a blue soleil sunburst pattern and features applied baton hour markers with slender, non-luminous dark hands. The design omits a seconds hand and a date display. The watch is presented on a light grey leather strap, which is original to the vendor's listing, equipped with a Patek Philippe 18k white gold pin buckle. The movement is reported to have been fully serviced by a professional watchmaker as part of the offering process.

Front view of the Patek Philippe Calatrava Ref 3520D, showing the blue soleil dial, 18k white gold case, and Clous de Paris bezel.
Front view of the Patek Philippe Calatrava Ref 3520D, showing the blue soleil dial, 18k white gold case, and Clous de Paris bezel. — Bulang & Sons. Rights pending — permission not yet requested. Original source

Catalogue identity

Source
www.bulangandsons.com
Category
Wristwatch · Dress watch
Maker / attribution
Patek Philippe
Reference
3520D
Catalogue / lot identifier
Source URL identifies the listing
Source-reported date
circa first half of the 1970s
Source-reported place
Switzerland
Source-reported serial
270xxxx

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 Patek Philippe reference 3520D features a 32mm case constructed from 18k white gold. The design is characterized by straight lugs and a distinctive Clous de Paris hobnail-patterned bezel. The case construction includes a screw-down caseback, contributing to the slim profile of the watch.

The dial is finished in a blue soleil pattern, which creates a sunburst effect that varies in appearance depending on lighting conditions. The layout is minimalist, featuring applied baton hour markers and slender dark hands. The watch design intentionally excludes both a seconds hand and a date complication to maintain a clean aesthetic.

Evidence for this section
  • “Its slim 32mm case, slender straight lugs and distinctive Clous de Paris bezel are beautifully proportioned.”
  • “Finished in a gorgeous mid-blue soleil pattern, it changes character beautifully depending on the light.”
  • “No date, no seconds hand, nothing to distract from the beauty of the dial.”

Movement and Mechanical Details

The watch is equipped with the calibre 175, an ultra-thin, manual-winding movement produced by Patek Philippe. The mechanical components are housed within the 18k white gold case.

The vendor reports that the movement has been fully checked and regulated by an experienced professional watchmaker to ensure operational status.

Evidence for this section
  • “Inside beats the ultra-thin, manually wound calibre 175”
  • “The movement has been fully serviced by an experienced professional watchmaker.”
  • “Fully checked and regulated by our experienced professional watchmaker”

Historical Context

The Calatrava line was introduced by Patek Philippe in 1932 with the reference 96. The reference 3520 series was introduced during the 1960s as a slim iteration of this design.

In 1972, the reference 3520D variant was released, reintroducing the Clous de Paris hobnail bezel to the Calatrava collection. The specific serial number 270xxxx associated with this example dates the object to the first half of the 1970s.

Evidence for this section
  • “Introduced in 1932 with the reference 96, the Calatrava became one of Patek Philippe's most enduring designs”
  • “In 1972, the Clous de Paris version, reference 3520D, brought the distinctive hobnail bezel back into the spotlight”
  • “Serial number 270xxxx dating to first half of the 1970s”

Open research questions

  • What is the complete serial number range for the 3520D production run?
  • Are there archival records documenting the production year for serial number 270xxxx?

Source evidence

Recorded claims and source quotations for Patek Philippe Calatrava Ref 3520D
FieldSource-reported valueSource quotation
Reference3520D“Patek Philippe Calatrava reference 3520D”
Case Material18k white gold“32mm case in 18k white gold”
MovementCalibre 175“Patek Philippe calibre 175, ultra-thin manual-winding movement”
Serial270xxxx“Serial number 270xxxx dating to first half of the 1970s”
BezelClous de Paris“Clous de Paris hobnail bezel and screw-down caseback”
DialBlue soleil“Blue soleil dial with applied baton markers and non-luminous hands”
Buckle18k white gold“Patek Philippe 18k white gold pin buckle”

Visible details

  • Clous de Paris hobnail pattern on the bezel
  • Blue sunburst dial finish
  • Applied baton hour markers
  • Manually wound movement without seconds indication

Research qualifications

  • Serial number is partially redacted as 270xxxx
  • Exact service history prior to the current vendor's assessment is not provided

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

Consulted source

Patek Philippe Calatrava Ref 3520D Blue Soleil Dial in 18k White Gold

Reviewed 2026-11-02 · Record a3465100e5

Terms in this record

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

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