On November 30, Zenith celebrated a famous caliber and the 100th birthday of the watchmaker who created it. Ephrem Jobin was the brains and hands behind Caliber 135. Introduced in 1948 at the height of a battle to achieve increased precision fought among several watch manufacturers, Caliber 135 included several innovative technical features that enabled it to win numerous prestigious awards and prizes, including an unprecedented 5 consecutive Neuchâtel Observatory chronometry prizes from 1950 to 1954. In all, the movement garnered about 200 honors, two-thirds of which were first prizes.
Ephrem Jobin with Zenith CEO Jean-Frédéric Dufour and Zenith watchmakers
Born in 1909 and likely the world’s oldest living watchmaker, Ephrem Jobin played a variety of roles in Zenith’s development. During his tenure from 1939 to 1954, he developed three complete calibers, including the 135. In 1946 he was commissioned to invent a 30mm caliber capable of meeting the requirements for the Neuchâtel Observatory competition. His recipe for success included a large barrel to increase the power reserve, and an oversize balance to enhance precision. This required a rethinking the movement design, including offsetting the minute wheel from the central axis to provide space for the enlarged balance. The observatory competition version of this legendary movement (Caliber 135.0) was equipped with a Breguet overcoil balance-spring, as well as a single or double arrow-shaped index or regulator ensuring balanced friction and enabling optimal adjustment. The movement’s high quality limited production. About 11,000 movements were produced, and watches with the movement are sought after by collectors today.
A vintage Zenith with Caliber 135
A Zenith Caliber 135 from a timing competition with one of many award certificates
Zenith is commemorating Mr. Jobin’s jubilee by issuing a special 100-piece limited edition watch in his honor. The company presented him with Number 100 at the birthday ceremony. The watch is powered by an automatic COSC-certified Elite 689 movement having notably benefited from the technical progress made during Mr. Jobin’s time at Zenith. The 18-carat rose gold case with sapphire crystals on either side frames an understated brown sunray dial graced by 18-carat rose gold faceted hands and hand-mounted applied hour markers. This handsome model conveys Zenith’s gratitude to Mr. Jobin for his major contribution to the history and development of the brand.