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International Watch Company - A Vintage 1948 Issued - Mark XI R.A.F. 6B/346 Military Pilot Watch

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A Rare and Desirable Military Issued IWC Mark 11 (Mk. XI) Post-WWII Airforce Chronometer Pilot's watch Which Was Issued in 1948 As Attested by Case Back Markings

An accurate and revolutionary piece of kit for the British Royal Air Force; not just for the UK but for many of the Commonwealth countries around the world. The Mark 11 allowed for a wholly different class of navigation as the aerial conflict intensified during the Second World War. This was to prove essential for coordinated bombing runs, and was built with the aid of military pilots from the Second World War. This watch was used by the navigator in an RAF plane in conjunction with a bubble-sextant to calculate the exact latitude and longitude of the aircraft. This method was in principle the same as that used by sailors to calculate their position ever since the development of the marine chronometer by John Harrison in the mid-eighteenth century. 

These particular watches were not produced in large numbers, and many were decommissioned from military service later in their lives, a few like this beautiful example, thankfully have survived! Many forum browsers and watch collectors consider these pieces to be the most desirable and revered British military watch out there (us included). This IWC does have a twin; the Jaeger LeCoultre Mk.XI, both of which are prized and only slightly different. (Heads up, we will have one of these coming to the site very soon once our watchmaker has completed a movement service if it doesn't sell to a reader of this first!)

It featured a soft iron core to fully encase the watch in an anti-magnetic housing, the dial also being made of iron to holistically encase the watch for accuracy's sake. The movement is extremely accurate, using a hacking complication to allow for the second hand to be precisely synchronised, and is chronometer accurate! The Mark XI is the pinnacle of British military watches: a carefully specified, refined design with supreme accuracy and solid craftsmanship. The case back is engraved '6B/346', the Ministry of Defence issue codes for the Mark XI. 

What's on offer

An iconic and must-have military watch for any collector worth their salt, and this is a particularly fine example if we do say ourselves! 

Built to the strict specifications required by pilots in their duties, this is a rare opportunity to own a piece of British aviation history as well as a stylish watch that can be worn every day. We have illustrated this watch worn with a NATO-style strap however a vintage look leather strap would also be a great pairing. 

The watch only shows minor signs of wear to the case, which one would not expect from a watch from 1948, a real testament to the build quality! The case back is engraved with the military arrow, known as the pheon, and 6B/346 283/48. The stark black dial is blemish-free and the Arabic numerals are crisp as is the arrow (Pheon) which denotes the watch as (former) military property.  

This watch is in simply stunning condition, the jewel of its crown being the beautiful Tritium lume markings on the dial and inserts on the hands, which have aged evenly over the years to a beautiful light pumpkin hue - giving a real warmth to the dial. At 36mm this watch is mid-size but it wears larger on the wrist whilst remaining comfortable. These watches are very much sought after and we don't expect this one to be around for long, especially with the beautifully aged lume - a real collector's piece. 

Additional information:

Made from

Case: Stainless steel

Dial: Black, Tritium

Crystal: Plexiglas

Bracelet: NATO Style strap

Technical specifications

Movement Type: Manual winding

Caliber: 89 

Jewels: 17

Purchase details

Condition: Excellent

Model reference number: Mark XI IWC

Year of issue: c.1948


12 months by VWS


Width (without crown): 36mm

Lug width: 18mm

Lug height: (lug to lug) 45mm

Wrist size: Adjustable