This particular piece features a well-proportioned 37mm steel case with a classic “stepcase” design—named for the distinct stepped bezel. The case-back has three notches, a detail that earned these models the nickname “Tre Tacche” from Italian collectors, meaning “three notches.” This case style is among the earliest water-resistant chronograph designs ever produced.

The 13ZN movement is one of the most celebrated in vintage collecting circles. Produced between 1936 and 1951, it followed the calibre 13.33Z and quickly became a benchmark for mid-century chronographs. These movements appeared in a wide variety of configurations—flyback and non-flyback, semi-instantaneous counters, monopusher setups, and central-minute layouts. By the mid-1930s, Longines was producing all components in-house, a rare achievement at the time.

The example offered here has a crisp case with well-defined steps and a case-back bearing an inventory number that matches the number engraved on the back of the upper-left lug—proof of matching parts. The dial is a silver-white tone with a black base-1000 scale, red telemeter scale, minute track, and black Arabic numerals. It’s signed “Longines” and “Anti-Magnetique” in elegant engraved (!!) fonts, with lovely even patina and blued hands that complete the look.

Included with the watch is an official Extract from the Archives, confirming delivery on 25 April 1942 to Ostersetzer, Longines’ agent in Italy. Also included is an email from Longines confirming that the dial is original, described in their records as: “white with tachymeter and telemeter scales and Longines Anti-Magnetic engraved on it.” A great detail to have— as this piece has stayed just as it left the factory ! The watch has been fully serviced by our watchmaker. We matched this historical important Chrono with a Bulang and sons leather strap , a great match we think .

We’ve always had a soft spot for these step cases—let’s be honest, they’re definitely some of the coolest cases a chronograph could have. Add the legendary 13ZN movement and heritage ? Come on, guys… no brainer!

Specifications:

Longines Chronograph “tre tacche ” 13 ZN step case chronograph reference 4974

37 mm screw down case “matching numbers “

Order number 621xxxx dating to the early 1940’s

Silver dial with multi scales , and blued hands “ bi – compax sub dials lay out

Triple signed (case, movement & dial)

Extract of the archives of Longines stating an invoicing in 1942 , sold to Italy

Longines hand-wound movement cal.13ZN

Bulang and Sons leather strap

Fully serviced by our watchmaker

One-year mechanical warranty

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