From Watches by SJX … Organised by the great and the good of Swiss watchmaking, including the Neuchâtel cantonal government, COSC and the Besançon Observatory, the biennial Concours International de Chronométrie, or International Chronometry Competition, professed a noble aim. It wanted to continue the tradition of the chronometer contests of the 19th and 20th century, not just for movements, but for finished watches destined for the purchase by consumers.
… But amongst the rules of the contest, one governing the provenance of the timepiece stands out. It reads: “All parts used to build the movement must be made within Europe.”
Image from blog Watches by SJX
By the late sixties Seiko dominated Swiss observatory chronometry trials, just before the contests were cancelled for good. From 1968 to 1970, 226 watches were certified by the Neuchâtel observatory and sold to the public as Astronomical Observatory Chronometers, making them amongst the rarest and most desirable Seiko timepieces ever.