This is an excellent dial and patina with the reference 769 the Chronomat, here is what I have found on the subject of this watch. The movement is stamped 'Premier' which means that this watch is from an advanced era, probably middle 1945 or so, the serial # denotes a production of post WW II. The watch is in full functional order, and the chronograph functions which have 45 minutes sub-counters, and the large red chronograph seconds hand counts down the seconds. The seconds hand at 9 o'clock functions as the actual seconds of the watch. http://www.breitling-museum.com/Breitling-Chronomat.html The Breitling Chronomat with its rotating slide-rule was patented in 1941 as war raged through Europe and other parts of the world, its design offering a welcome respite from the plethora of military and military-inspired watches of the period. The Chronomat's emphasis on engineering and mathematics, science and industry seemed to offer hope for a future when the war would be over and reconstruction could begin. Although often thought to be the first slide-rule wristwatch on the market, the Breitling Chronomat was in fact the second. The Mimo-Loga, a non-chronograph, was introduced during 1941 before the Breitling. The Mimo-Loga, including a later version sold under the Girard-Perregaux brand-name, is virtually unknown today. In 1952, the outstanding usefulness and success of the Chronomat inspired the birth of what has since become the most famous Breitling of all, the Navitimer, a chronograph with the slide-rule redesigned for civil aviation pilots. The Chronomat went on to be produced in many forms including a version of the first automatic chronograph watch in the late 1960s and a quartz non-chronograph during the 1970s. Then in the 1980s it was reborn in a very different form as a pilot's watch and without the slide-rule. This new incarnation was designed with input from Italian military pilots. The Chronomat has remained one of Breitling's most successful watches for over sixty years. Contrary to general belief, it is not the Navitimer but the Chronomat that has in recent years proved to be Breitling's most popular model and biggest seller. 1940 
Breitling apply for a patent for the design of a rotating watch bezel with an outer circular slide-rule scale incorporated beneath the crystal and turning with the bezel. The patent also specifies some technical aspects of the inner and outer scales and how they may be used for computations. 1941 
The Chronomat is first advertised during 1941 and therefore may have been released for sale in that year - research is still on-going on this subject. Certainly a prototype is seen in 1941 but this is different in several details from the watch that would be sale to the public during the following year. 1942 
It is generally accepted that the Chronomat made its public sales debut in 1942 and this is the date that has been quoted for many years by the Breitling company. The circular slide-rule design of the Chronomat has come to be known as the 'Type 42' to differentiate it from the 'Type 52' slide-rule first seen on the Navitimer supposedly in 1952 (NB: some Breitling experts believe the actual launch of the Navitimer was later than 1952). The 1940's Chronomat is regarded by many collectors as one of the most attractive Breitlings ever made, a true classic. There is a red 0 - 100 scale near the middle of the dial which can be used for reading 1/100ths of a minute which facilitates computations using the slide-rule. The Swiss cross and the number 217012 on the dial refer to the Swiss government patent that was granted in 1940. In common with other Breitling chronographs at this time, the minute register is marked at 3, 6 and 9 minutes as long-distance phone calls were charged in 3-minute increments in most countries. Long distance and especially international 'toll' calls were very expensive at this time; connection was via the operator; there was no direct dialling, and it was important not to go 'over' one's chosen duration and become liable for a charge of a further three minutes. The turning bezel includes an outer telemeter scale which is used for measuring the distance of a phenomenon that is both visible and audible, eg lightning/thunder. The movement is the Venus 175, 17-jewels with a centre chronograph hand recording seconds, a minute chronograph register at 3 o'clock recording up to 45 minutes, and a running seconds hand on the sub-dial at 9 o'clock. There is no Incablock shock protection and initially the movement is not signed either 'BREITLING' or with the three-letter Breitling movement code, 'WOG'. (Note: small variations occur in the appearance of some of the components of the Venus 175 as fitted in the Chronomat). The ref 769 was also available with a black dial in both luminous and non-luminous versions. The non-luminous variant had thinner hands. Smaller numbers of these were manufactured and sold than the silvered dial version. The Chronomat was conceived and then promoted as a watch for scientitists, engineers, mathematicians; for timing and financial calculations. It was specifically not designed for military men or pilots. By the end of the war the watch was advertised with a particular emphasis that would appeal to hard-working men of achievement in the new age that beckoned after the dark days of the earlier 1940s.