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The Encyclopedia of Horology

Wristwatch · Chronograph

Rolex Oyster Chronograph Monoblocco Antimagnetic reference 4500

Partially verified

According to the auction catalogue, this Rolex Oyster Chronograph Monoblocco Antimagnetic, reference 4500, dates to circa 1946. It is constructed in an 18-karat yellow gold case measuring 35 mm in diameter, manufactured by Spillmann with hammer-head punch mark 136. The round case features round chronograph pushers, an original signed screw-down Oyster crown, and a screw-down case back. The patinated silver dial displays applied hour markers, painted minutes, tachymeter and telemeter scales, and two sub-dials: small seconds at 9 o'clock and a 30-minute counter at 3 o'clock. The source reports a manual-wind Calibre 23 movement signed Rolex with a ROW balance bridge engraving, accompanied by a leather strap with a signed gold-plated pin buckle.

Three-quarter view of the Rolex Oyster Chronograph reference 4500 in yellow gold on a dark leather strap
Three-quarter view of the Rolex Oyster Chronograph reference 4500 in yellow gold on a dark leather strap — GROS & DELETTREZ. Rights pending — permission not yet requested. Original source

Catalogue identity

Source
www.invaluable.com
Category
Wristwatch · Chronograph
Maker / attribution
ROLEX
Reference
4500
Catalogue / lot identifier
461
Source-reported date
Vers 1946
Country
Switzerland
Source-reported serial
418846

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 Construction and Identification

This Rolex reference 4500 is identified by the manufacturer as a 'Monoblocco' chronograph, a term applied by the source to models where the bezel is integrated into the case structure. The 35 mm round case is constructed from 18-karat yellow gold (750).

Visible features include round chronograph pushers and a signed Rolex Oyster screw-down crown. The case was produced by Spillmann, indicated by the 'hammer head' hallmark 136.

Evidence for this section
  • “Boîtier : rond réalisé par Spillmann (poinçon tête de marteau no. 136)”
  • “Diam. 35 mm”
  • “couronne signée Rolex Oyster”
  • “surnommée Monoblocco en raison de sa lunette intégrée au boîtier”

Dial Configuration

The watch features a silvered dial exhibiting a uniform mottled patina and minor staining. The layout includes applied hour markers, painted minute tracks, and integrated tachymeter and telemeter scales.

Chronograph functionality is presented via a two-register setup: a 30-minute counter positioned at the 3 o'clock mark and a small seconds register at 9 o'clock. The dial is signed and includes the 'Swiss Made' designation.

Evidence for this section
  • “Cadran : argenté patiné« Swiss Made », index appliqués, échelle tachymétrique et télémètre, minuterie peinte”
  • “compteur des 30 minutes à 3H, petite seconde à 9H”

Movement and Reported Specifications

The timepiece is powered by a manual-wind Calibre 23 movement signed by Rolex. The movement is distinguished by a 'ROW' engraving located on the balance bridge.

The watch is fitted with a leather strap finished with a signed gold-plated pin buckle. The condition report indicates that the movement and chronograph are functional, but recommends a standard service.

Evidence for this section
  • “Mouvement : mécanique à remontage manuel, calibre 23, signé Rolex avec gravure ROW sur le pont de balancier”
  • “mouvement et chronographe fonctionnel, prévoir révision d'usage”

Open research questions

  • What is the historical significance of the 'ROW' engraving on Rolex Calibre 23 balance bridges from this production era?
  • Does the 'hammer head' punch mark 136 serve as a unique identifier for Spillmann-manufactured Rolex cases from the 1940s?

Source evidence

Recorded claims and source quotations for Rolex Oyster Chronograph Monoblocco Antimagnetic reference 4500
FieldSource-reported valueSource quotation
Reference4500“Réf. 4500”
Serial Number418846“No. 418846”
Case Material18K yellow gold (750)“or jaune 18K (750)”
Case MakerSpillmann (hammer head punch no. 136)“réalisé par Spillmann (poinçon tête de marteau no. 136)”
CalibreCalibre 23“calibre 23”
Case Diameter35 mm“Diam. 35 mm”
Gross Weight53.5 g“Poids brut : 53.5 g.”
Estimated DateCirca 1946“Vers 1946”

Visible details

  • Two-register chronograph dial configuration with sub-dials at 3 and 9 o'clock.
  • Round chronograph pushers flank a fluted winding crown on a yellow-gold case.
  • Dark textured leather strap fitted with a yellow-toned pin buckle bearing a coronet emblem.

Research qualifications

  • Movement caliber and case back interior are not shown in the lot photograph.
  • Case maker hallmark, reference number, and movement engravings are source-reported and not directly visible.

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

Consulted source

At Auction: ROLEX, ROLEX Oyster Chronograph Monoblocco Antimagnetic

Reviewed 2026-10-25 · Record 479aa00a48

Terms in this record

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

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