1970s Zenith "Shadow Prototype" Chronograph PVD 'Cal. 146 HP'

The “Shadow Prototype” stands as one of the rarest and most compelling watches in Zenith’s history — a visually and metaphorically stealthy chronograph developed in the early 1970s, shortly after the launch of the groundbreaking El Primero. Never commercially released, this prototype represented an experimental vision for a new generation of Zenith chronographs, housed in a PVD-blackened steel case that was radically ahead of its time.

For decades, this watch was more rumor than reality — whispered about by longtime employees, but never officially documented. That changed during Zenith’s 50th-anniversary celebration of the El Primero, when the team uncovered a sealed attic in the Le Locle manufacture. Inside, amid archived components and forgotten prototypes, they found an original black chronograph — physically confirming the existence of the so-called “Shadow.”

The watch was powered by the manually-wound Cal. 146 HP chronograph movement, a caliber shared by both Zenith and Movado during their collaborative period. Surviving examples show variations in the movement bridges — some signed Zenith, others Movado, and some entirely unsigned — adding to the mystery and allure of the few pieces known to exist.

With only a handful ever made and none officially sold to the public, the Shadow Prototype is an artifact of innovation and design audacity. It served as the direct inspiration for the modern Revival Shadow — but the original, with its raw, utilitarian case and minimalist dial, remains a genuine relic of Zenith’s boldest era.

SPECS

Stock # ZNTSHDWPRT
Brand Zenith
Style "Shadow Prototype" Chronograph
Model N/A
Serial N/A
Size Men's
Material PVD Stainless Steel
Dial Matte Black
Millimeters 41
Strap 2pc Zenith Alligator Leather Strap W/ Zenith Tang Buckle
CASE & BRACELET

The black PVD case remains in extremely crisp and unpolished condition, showing some minor spots of wear and only very minimal spots of fading to the factory PVD finish. The case retains its characteristic and original chrome-plated brass pushers and unsigned crown, which show some expected light wear. The case back retains crisp finishing throughout with nominal signs of previous wear present. The watch was sourced on an era-correct 2pc black Zenith alligator leather strap with an era-correct Zenith tang buckle.

DIAL & HANDS

The original matte black dial is in near-perfect condition, with the only element of age being some brassing present at the very edge of the dial between 10 and 11 o'clock, otherwise the dial is flawless. The tritium lume plots all remain fully intact when inspected under UV light and have achieved a lovely creamy patina. The original non-luminous hands are in perfect condition.

ACCESSORIES

None. The watch is functioning perfectly and keeping time, previous service history is unknown. A movement service can be provided upon request.

Dimensions: 41mm

Box, Papers, etc.: Watch Only

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