IN-DEPTH: The Lineage of the Longines Czech Aviator Chronometre


The so-called "Tartarugone" is a chronometer wristwatch that was produced by Longines for Czech aviators before, during, and after the Second World War. The Tartarugone features a unique case shape and has greatly evolved over time—utilizing three different movements. The second series, which was made in a very limited quantity, is seldom seen in good condition. While the other variations are not as rare, they are a financially-accessible alternative to the higher-priced Longines pilot's watches of the early 20th century. Let's take an in-depth look at the history of this fascinating wristwatch.


A Czech Pilot Sporting His Longines.

By the end of the 1930’s, the Czechoslovakian armed forces were considered amongst the best equipped in Europe. The Czech Air Force consisted of 67 regiments. The standard bombers flew the Aero A.100 and AB.101 planes, the light bombers flew the fast twin-engine Avia B71, and the heavy bombers flew the Avia Fokker F-lX and the Bloch MB200. 155 planes were used as bombers, alone. Most of the 320 reconnaissance aircrafts were Letov S.328 biplanes. In 1938, Hitler promised the release of the Germans in the Sudetenland on the border of Czechoslovakia. The first attempt of the Germans to occupy the Sudetenland triggered the mobilization of the Czech air force in May of 1938. From then on, the Czech's involvement in the war only heightened.


The first series features the caliber 15.94, the primary movement used in the assembly of this watch. The serial numbers often dated these pieces to the early 1920’s because the casebacks were stamped long before the actual construction of the cases. In fact, most movements were stamped with 5.4 million serial numbers, dating the movements to around 1936/37.

Findings from our thorough research exhibit the differences and similarities of the first series models: 

Serial 3940000, anticorrosion, signed, enamel dial. 

Serial 5.6 million, anticorrosion, not signed. 

serial 5660000, anticorrosion, not signed. 

serial 5570000, anticorrosion, not signed. 

serial 5420000, anticorrosion, signed, enamel dial.

serial 5660000, anticorrosion, not signed, enamel dial.

serial 5463000, anticorrosion, not signed, enamel dial. 

The second series, the rarest series, houses the caliber 15.26ABC. We can find this movement in the following references: 

Reference 20440 serial unreadable not assigned, anticorrosion, baton luminous spheres. 

Reference 22785 serial 6600000, anticorrosion; not assigned. 

Reference 22322 serial 6490000, anticorrosion; not assigned. 

Reference 22580 serial 6640000, anticorrosion; not assigned, 2 pieces, spheres luminous baton. 

Reference 23684 serial 5724000, assigned, stainless steel, enamel.

The third series, the final and most common variation of this watch, was produced in 3582 pieces. As you can see, the references do not differ much:

Reference 20067 7.45 serial, stainless steel, signed. 

Reference 23313 serial 7.18, 7.11 7.479, 7.45 7.16, steel, not signed.  

Reference 23314 serial 7.4, anticorrosion, not signed, crown step. 

Reference 23519 serial 7450000, stainless steel, not signed. 

Reference 23315 serial 7430000, stainless steel, not signed, corona step. 

Reference 23684 5.72 serial, 7:52, 7:47 7:43, 7:45, stainless steel, signed, enamel dial. 

Reference 23384 serial 7450000, stainless steel, not signed. 

Reference 22647 serial unreadable, stainless steel, signed. 

Reference 23694 serial 7520000, stainless steel, signed. 

Reference 23510 serial 7450000, stainless steel, not assigned. 

Reference 20164 serial 7:5, anticorrosion, not assigned. 

THE THREE CALIBERS (15.94, ABC 15.26, 15.68z)

Click To Enlarge

The 15.94 was the first of the three calibers used in Tartarugone. This caliber was initially used in pocket watches circa 1902-1904, and was first seen in a wristwatch at some point during 1917. This caliber is 34.7 mm in diameter and 5.65 mm in height. Six plates in the movement are finished in a frosted gold plating, featuring a bi-metallic Breguet spiral.

Click To Enlarge

In chronological order, this was the second caliber used in the production of the Tartarugone.  Created and launched in 1929, the now-popular ABC 15.26 is known for its “ham-like“ shape. Due to the Great Depression, Longines had poor sales, which then resulted in the low production of this caliber. The only significant difference between the aforementioned 15.94 and the 15.26 is that this movement had slimmer dimensions (4.5 millimeters in height).

Click To Enlarge

Upon request by the Czech government, Longines built the 15.68z to the exact specifications as the previous movements. Instead of traditional gold plating, Longines applied gold electroplating—though this did not alter the movement’s appearance.



The dials produced for the Tartarugone were either a black semi-gloss finish on a metal base or a black gloss finish on a porcelain enamel base. Both dials featured white Arabic numerals and indices. The following discusses the construction and layout of the dials in further detail.

Enamel Dials: 

All writing on the dial is in a white, legible font. The word “anti-magnetique,” can often be found directly above the subsidiary seconds dial.

Close-up of "Anti-magnetique" Written On The Dial


It is very difficult to find these enamel dials in mint condition, since the enamel was typically subject to breakage due to shock. Though it did not work completely, to help prevent breakage, enamel dials were built significantly thicker than the metal dials. Longines with italic lettering on dials are most likely watches made prior to the war; those with block lettering were made either during or post-war.

Metal Dials: 

Because of the extreme fragility and high cost of porcelain enamel dials, Longines swapped the original enamel dials for blacks metal dials. The technique used to fabricate these enamel dials was called "à épargne.” The finish was not too dissimilar from that of the enamel dials (semi-gloss). Additionally, the lettering remained the same—with the exception of the word “anti-magnetique" which changed fonts


Most mid-1930's models in existence today bear the engraving "Majetek Vojenske Spravy," or "Asset Of Military Administration."  These engravings, hand-stamped by military personnel after receiving the fully-assembled watches from Longines, signified the military's ownership of a timepiece. If a watch does not exhibit an engraving, it does not mean the watch was not used for military purposes—it's just that there was probably not enough time to complete the engraving


This advertisement is the only known example of an advertisement in which the Tartarugone is visible and its description is highly-detailed. 

Here's an excerpt from the text above translated into English:

“LONGINES watches win in all countries. There's big attention recently, mostly pertaining to aviation, which is closely connected to the need of providing pilots with the most perfect inventions in modern science. LONGINES pilot watches are mainly distinguished by unique, beautiful stainless steel cases, surely it's our pride and joy. The case is pure technical perfection and is highly resistant to weather conditions, being both dust-proof and shock-proof. To satisfy both needs, LONGINES watches are sold not only with the long leather band intended for the real pilots, but also with the short (normal) band made from pigskin leather only intended for sportsmen...."




The legendary Tartarugone boasts incredible accuracy, superior durability and an indomitable look and feel. But what gives the Longines “Czech Aviator Chronometre" most of its character is not as much related to technical features, as it is principally to this watch’s glorious history. 

Written By Adriano Davidoni

Translated By Luke Rottman

Click HERE To Read The Full Story In Italian On Adriano's Website: Longines Passion.