The dial is both highly functional and visually compelling. On the outer edge, it features a tachymeter scale printed in blue with a base of 1000 units, designed for use in conjunction with the chronograph. Closer to the dial's numerals, sits a 60 seconds scale, printed in black, used to time elapsed seconds.

A base 1000 scale on a chronograph dial is a specialised tachymeter scale designed to convert elapsed time directly into a rate per 1000 units of distance, typically meters or kilometers depending on the application. Instead of requiring mental calculation, it allows the wearer to read the result almost instantly after timing an event over a known distance or interval. In practice, the chronograph would be started at a reference point and stopped after a measured distance or event, with the base 1000 scale providing a direct reading of speed or rate. This was particularly useful in aviation, military navigation, and artillery spotting, where rapid and efficient conversion of time into operational data was essential. Combined with a flyback chronograph, which allows immediate resetting and restarting of timing, it enabled consecutive measurements to be taken quickly and accurately without interruption.

The stunning dial layout is completed by two prominent sub-dials, often referred to as “big eyes.” These oversized registers display the running seconds and the 30-minute chronograph counter, offering both improved legibility and a distinctive aesthetic.

At the heart of this watch lies the legendary 13ZN movement. This manually wound flyback chronograph features 17 jewels, operates at 18,000 vibrations per hour, and is fitted with a Breguet hairspring for enhanced precision.

In the 1940s and 1950s, the flyback chronograph function was not merely convenient, but essential. These watches were used as navigation tools by pilots and as timing instruments in military applications, including artillery coordination. Longines was far ahead of its contemporaries, as few manufacturers attempted to produce a flyback chronograph until nearly two decades later.

This particular movement has undergone an extensive three-month overhaul to restore its functionality. The result is a fully operational flyback chronograph with excellent performance and strong overall accuracy, including the invoice of that full service overhaul.

The watch retains its original blued steel hands, produced using a traditional technique known as thermal bluing. This process involves heating steel components over brass until they reach the precise temperature at which the metal develops its characteristic deep blue hue.

Achieving a consistent color requires exceptional skill and patience. Even a slight deviation in temperature can result in a finish that is too dark or uneven. In the 1940s, this was a task reserved for highly experienced watchmakers.

The hands on this example display a rich and even tone, a testament to the craftsmanship involved and their excellent state of preservation.

We conclude with a perspective from renowned collector and author John Goldberger:

“For me, Longines were the best chronograph producer in the 1940s. I think they were better than Patek Philippe, Vacheron Constantin and Rolex because they made their caliber in-house. The only other brand producing the whole movement at this time was Universal Genève, and there was a big difference between that and what Longines were producing.”

This watch stands as a clear reflection of that legacy. A technically advanced chronograph, executed with a level of quality and attention to detail that continues to resonate with collectors today.

The watch has been fully serviced; in fact, it has been handled by one of the most skilled watchmakers in the Netherlands, a watchmaker with cupboards full of original parts for watches of this calibre. This Longines 13ZN has been fully serviced at a cost of over €2,000 (receipt will be delivered with the watch) and will be sold with our comprehensive two-year warranty.