aljoux 72, El Primero, ETA 7750, Lemania 861, Longines 13ZN: all these calibre references are well-known in the watch industry for powering some of the most famous chronographs out there – vintage Rolex Daytonas, Longines, Zenith El Primero, Breitling Chronomat and Omega Speedmasters. But what about the other manufacturers that tried hard and sometimes failed to come up with their own version of what a chronograph should look like, and run like?