1940s 18ct gold round vintage Longines Chronograph watch
A 1943, 18ct gold round vintage Longines Chronograph watch. The case measures 35 mm in diameter with 18mm lug size. The Swiss Made case is signed Longines, 18K and numbered 6117185. The fabulous 13ZN manual wind movement is signed Longines with 17 jewels and numbered. The silvered dial has raised gold Arabic number 12, raised gilt dot hour markers, with two subsidiary dials recording minutes and seconds, outer blue and red telemetre scale and fine gilt hands. The dial is signed Longines above the centre.
In 1936 Longines began to produce one of the most technologically advanced chronograph movements at the time, the Calibre 13ZN. Longines developed the first chronograph for the wristwatch, the 13.33Z, but the 13ZN, was the first chronograph mechanism equipped with the flyback, or retour-en-vol, function. The 13ZN had 17 jewels; a diameter of 29.80 mm and height of 6.05 mm, and beat at 18,000 vph, and was equipped with a Breguet hairspring. The 13ZN movement was expensive to produce, particularly when compared to the ebauches that other major brands had access to. During this period of time, Longines invested heavily in another round of research and development to produce a less costly version of the 13ZN, but still retaining the flyback functionality that was, at that time, unique to Longines. After producing the 13ZN for about 11 years, the 30CH was introduced in 1947.
