Calibre 30CH

Notes

The 30CH project began in 1944 with the intended goal of making a less expensive and easier to produce chronograph movement than the 13ZN (Itself created to be less expensive and easier to produce than the 13.33Z). They hoped it would better fulfill the extreme demand during WWII for wrist chronographs. However it was not until 1946 after the war had already ended that Longines was able to devote the capital necessary to create the tooling for the 30CH project. The 30CH was the last in-house wrist chronograph calibre developed by the company and was discontinued in the 1970s when Longines merged into ASUAG and gained easy access to Valjoux Calibres since Valjoux was also part of the ASUAG conglomerate. It was discontinued for the same reason as its two predecessors, namely that it was too expensive and resource intensive to produce economically at scale. In the late 60s/early 70s Longines changed its movement naming structure and referred to the 30CH as the 530. it also produced a version without running seconds that it called the 538. While the latest sold example of this calibre happened in 1972-1973, it is likely that production of the watch ceased before this time, probably 1970-1971 and examples were sold from existing stock.