Time again to exercise the Bucherer two-register chronograph with a 17-jewel Landeron calibre 48 movement. The calibre 48 was introduced circa 1937, and produced until 1970. This one is in a gold filled “clamshell” case with steel back, and I estimate it would be circa mid 1950s. Close to 70 years old. I’ve owned it for about 20 years, but hadn’t worn it until I serviced it, early in January. (Finger mark on the balance cock no longer there since servicing!)