ROLEX Prince "Railway" Black Dial 1940s

Serviced prior to delivery
Timegrapher +100s/d 225° 1.6ms

The Rolex Prince has long been admired as the watch that made precision visible on the wrist. Built around a movement conceived for the rectangular form rather than adapted to it, the line carried Rolex's earliest reputation for chronometric accuracy into an unmistakably Art Deco silhouette. This example is distinguished by a solid 18K gold stepped case — the configuration collectors know as the "Railway" — paired with a black dial reading CERTIFIED PRECISION.

The case is solid 18K gold, measuring 21.5mm across excluding the crown and 45.5mm from lug to lug. Its exceptional length is the defining feature: stepped flanks run the full height of the case like a pair of rails, while the lugs sweep outward in the sinuous cabriole curve that gives the profile its sculptural quality. Nothing is applied for decoration, and the shape alone carries the watch. The inside of the case back carries the reference, 3937.

Against the gold, the dial is a deep black, its lacquer holding light rather than scattering it. The dial has been refinished, the original surface having aged past legibility, and in the course of that work the lower text was rendered CERTIFIED PRECISION where the original read CHRONOMETER. Applied pyramid studs mark the hours with faceted darts at the quarters, and the hands are original to the watch, slim dauphines stretching across the full width. Below center a recessed small seconds register sits between two vertical rails.

At its heart beats the manually wound Caliber 300, an 18-jewel movement built by Aegler of Biel, running at 18,000 vibrations per hour with a Breguet overcoil and Rolex's patented Superbalance. The bridges are signed CHRONOMETER and TIMED 6 POSITIONS — the certification the dial once carried, still legible on the movement itself. To fill the elongated case, the going train was extended with two intermediate wheels carrying torque from the barrel toward the escapement, an architecture that exists nowhere else in the Rolex catalogue. The watch will be fully serviced before delivery, and the daily ritual of winding reinforces the connection between the wearer and the mechanism within.

Completing the watch is a gold-tone expansion bracelet in gold-plated stainless steel, not original to the watch but carefully matched to complement the case and preserve its period character. The lug width is 15.5mm, and the bracelet fits wrists up to approximately 20.5cm.

Elegant, purposeful, and unmistakably vintage, this Prince captures the moment when Rolex chose to prove itself through accuracy rather than ornament.

HISTORY

The Prince was Rolex's answer to a question the 1920s had only just begun to ask: could a wristwatch be trusted the way a pocket chronometer was? Its answer was Caliber 300, developed at Aegler S.A., Fabrique des Montres Rolex & Gruen Guild A., the Biel manufacture that supplied Rolex in Geneva and shared its engineering with Gruen in America. Rather than shrink a round movement into a rectangular case, Aegler designed the calibre for the form itself, stretching the train so that torque reached the escapement through two intermediate wheels. Adjusted in six positions at a time when official certification asked for five, the Prince became the first wristwatch made in significant numbers to carry a chronometer certificate, and the foundation on which Rolex built its case for precision.