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 offered a welcome respite from the overabundance 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.

A 1940's stainless steel manual wind gentleman's Breitling 'Type 42' Chronomat wrist watch, Swiss patent 217012. Tonneau shaped case numbered 694842 above 769 and fitted to an associated tan brown leather strap.

A 1940’s stainless steel manual wind gentleman’s Breitling ‘Type 42’ Chronomat wrist watch, Swiss patent 217012. Tonneau shaped case numbered 694842 above 769 and fitted to an associated tan brown leather strap.

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. 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 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 in 1952. The 1940’s ‘Type 42’ 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.

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.