Although wristwatches have been a standard piece of military equipment at least since the distribution of trench watches during WWI (often with metal grilles protecting their glass crystals), apparently the first large-scale attempt to standardize their design came near the end of WWII when the British War Department published new requirements for an armed forces wristwatch. Twelve companies (Buren, Cyma, Eterna, Grana, IWC, Jaeger LeCoultre, Lemania, Longines, Omega, Record, Timor, Vertex) responded with conforming designs for what are commonly called WWWs (watch(es), wristlet, waterproof) or Mark X (after the IWC version?). Among the requirements were matte black dials with luminous hands, numbers and indicies, subsidiary seconds, shatter-resistant plastic crystal, a case resistant to water, dust and shock, and a high-quality, isochronal and robust movement. The Mark X and later Mark XI (for aviators, featuring center seconds) wristwatches have since become the prototypes for an entire sub-industry of modern watches of 'military' or 'aviator' style. Besides being interesting in themselves, this 50+ year run of admiration, emulation and development indicates that this configuation has a permanent aesthetic and practical appeal, and thus the originals are highly sought and collectable.
While the superficial distinctions amongst the twelve manufacturers' offerings are relatively minor (cases of stainless steel, nickel alloy, chromed and matted base (brass?), diameters from 33-38mm, and dial variations), each also supplied their own movements, then all of prorietary design. The most famous Mark Xs are of course those of the 2 companies with the longest military-supply traditon, IWC and Omega, featuring respectively their Caliber 83 and 30T2 movements. Both of these are beautiful and proven excellent, likely amongst the best high-production, handwinding, time-only movements ever, but my favorite Mark X movement is that of Jaeger-LeCoultre, the present Caliber 479. Perhaps because it has long been a 'movement house', while the other manufacturers simply used their best complying stock movement, JLC actually designed a new caliber which was used exclusively in their Mark X watches. As a result, if you desire a watch with this movement , you will have to have a Mark X, and while the population of both military and standard watches housing Cal. 83 and 30T2 movements probably runs into the millions, that of the Caliber 479 is likely closer to 10,000 (I would love to have a definitive figure!).
Click the pictures for even larger!
The Caliber 479 is 12.5 lignes (just over 28mm diameter), gilt in yellow gold and employs 16 jewels. Close examination shows that besides being a beautiful and elegant design, great care has been taken in its functional finishing.
The bridges are softly and evenly beveled, the jeweled countersinks are polished and very smooth, and the balance and gears are wonderfully wrought, almost delicate, with thin spokes, and beveled all around. All the steel parts are finely finished, with high polish on the regulator, screws and fabulously sculptured anchor!
Although I have had a display back installed on my watch, I have certainly retained the original back, with the Ministry of Defense markings.