Here we a good example of an all original 1943 Longines 6B/159 WW2 RAF Pilot watch. It has the 32.25mm case with the Duralim centre and steel snap on bezel and case back. The dial is bright and clean, with the black Arabic numerals and minutes/seconds track. It has a pleasing even speckled patination. The thermally blued hands are all original, with the standout Diamond tip minute hand. To the right is the original, well sized onion style crown. To the rear, the case back has been crudely polished, with the issue markings having been removed. Inside it is signed with the reference 22453. The watch is powered by the Longines calibre 12.68N movement, which has been recently serviced and is keeping reliable time.
 
The 6B/159 watches were issued to pilots and navigators in the RAF who required extremely accurate timekeeping. Other crews with less sensitive timekeeping needs were issued 6B/234 watches. The 6B’s were manufactured by Omega, Jaeger-LeCoultre and Longines, with the most famous being the Omega example. However, the Longines examples are rarer than the Omega 6B/159s and arguably more distinctive. The non-traditional diamond shape to the minute hand is eye-catching, as opposed to the Omegas ‘whip’. The crown is also standout with its larger size and onion design. 
 
The 6B code is the RAF stock code for navigational equipment to be used onboard an aircraft. The watches have the clear central second hand, vital for accurate timing and use in an aircraft. To further aid this, the central second hand also has hacking function, allowing for exact second hand setting.
 
The watches were vital in navigation and could be used to make dead reckoning calculations. Dead reckoning is the process of calculating the current position of a moving object (a plane), by using a previously determined position (fix) and incorporating estimates of speed, heading and elapsed time.
 
 
 
 
 
The Duralim cased Longines, along with the Omega, were issued from 1942 onwards.
 
Examples without marked backs are somewhat of a grey area. Firstly, there were no civilian examples of these watches. They produced solely for military use, under military specification.
Some watches were taken from surplus, cased in Dennison cases and sold after the war. Other unmarked examples tend to be from 1944 which indicates that they may have never been issued but were kept as spare stock. 
The third reason for non-marked cases are the removal by those who kept them post WW2 issue. The watches were never meant to be kept and were supposed to be returned. However, people wanted to keep the watches that they were issued, understandable with them being trusty companions throughout the war. In order to avoid arousing any suspicion, individuals would polish the backs to remove the markings, to prevent the watch being traced.
 
With increasing appreciation of these pieces and Longines drive to embrace heritage, at Baselworld in 2018, Longines announced the Longines Heritage Military RAF Re-Edition watch. This is a full steel construction, with a larger case size of 38.5mm. It is an excellent modern re-issue with the faux patina dial and handset. 
 
Why not get yourself an original piece of history? These are beautifully simplistic, yet reliable and sturdy timepieces, that have a story to tell.
 
Please see the images as these compliment and aid the description provided below.
A further condition report is below.
 
Dial: 
The dial is original and is in good condition for the age. It is an off-white tone with light speckled marking associated with age. The signing is good and clear in the black tone, without wear. There is some slight marking to the track on the left hand side between 9 and 11 O’clock.
 
Hands: 
The hands are all original. They are thermally blued and have oxidised with some purple/brown tones. There is no bending or scratching and they are in good condition.  
 
Glass: 
The acrylic crystal is a replacement which is in perfect condition.
 
Crown: 
The crown is formed of Stainless Steel and is original. It is in good condition and has the onion design. 
 
Case:
The case is formed of Duralite to the centre and shows signs of its age. There is scratching and darkening as expected with age. The bezel is stainless steel and has a polished finish, with some light scratching. The lugs are good, with the fixed bars being strong.  
 
Caseback:
The snap-on case back is stainless steel and has the polished finish. It has marking from turning and polishing. The issue markings were often polished off when people kept the watches after the war. The crude nature of the polish shows this to have likely occurred. 
 
Strap: 
The watch comes on a period leather strap with metal tabs for fixed lugs. It is in good vintage condition. 
 
Movement: 
The movement is a Longines calibre 12.68N. It is a manual wind movement, with sweep central second. It has a jewel count of 17 and a frequency of 18,000 BPH. 
 
The movement has been recently serviced. It’s keeping time to within +/- 30 seconds a day, with an amplitude of 310 degrees and a beat error of 4.0m/s.
 
Case Dimensions:
Case width: 32.25mm
Case width with crown: 35mm 
Case length: 32.25mm 
Case length lug to lug: 43.3mm
Case Depth: 11.5mm
Lug width: 16mm