If you've spent any time researching vintage Rolex watches, you've probably noticed two tiny Greek letters sitting either side of the Swiss Made text at six o'clock on certain dials.

When vintage Omega enthusiasts discuss the company's greatest movements, names such as the calibre 321, 30T2 and 564 are often the first to appear. Yet one movement quietly sits at the turning point between Omega's pre-war precision watches and the legendary Seamasters and Constellations that would follow: the Omega calibre 343.

Mention Zenith and most enthusiasts immediately think of the El Primero. Others picture elegant 1950s dress watches or beautifully proportioned pilot watches from the 1940s. Yet beneath that reputation for precision lies a manufacture that has never been afraid to experiment.