ZENITH CALIBER 135 Zenith introduced caliber 135 in 1948, during an era of intense competition among watch manufacturers to produce the most accurate wristwatch movement. Designed by Ephrem Jobin, caliber 135-O incorporated several innovative technical solutions that led it to win numerous chronometer prizes at the Neuchâtel Observatory, including five consecutive first-place awards between 1950 and 1954. In total, the caliber achieved approximately 200 individual awards, two-thirds of which were first prizes, as well as five team prizes. One of the key technical features of caliber 135-O was an oversized mainspring barrel, allowing for extended power reserve. Large balance wheel played a decisive role in improving timekeeping precision. This approach required a complete rethinking of movement architecture, including relocation of the minute wheel away from the central axis to make room for the enlarged balance assembly. Approximately 11,000 caliber 135 movements were produced for commercial use in three different series between 1948 and 1962. This watch belongs to the third and final production series, manufactured around 1962. ⸻ ZENITH 135 AND KARI VOUTILAINEN In 2022, Kari Voutilainen was commissioned by Zenith to finish ten original Zenith 135-O observatory competition movements as wristwatches. For these restored movements, new dials and hands were produced in Voutilainen’s Comblémine atelier. Watches were cased in 38 mm platinum cases and released as Zenith Calibre 135 Observatoire Limited Edition. These collector pieces were sold through Phillips auction house at a price of CHF 132,900 per watch. ⸻ TECHNICAL SUMMARY •Brand: Zenith •Model: 2000 Chronomètre •Year: 1962 •Case material: Stainless steel •Case diameter: 35 mm •Dial: Silvered soleil •Lume: Radium •Hands: Original radium •Crown: Original Zenith star crown •Case condition: Unpolished •Caseback: Engraved •Movement: Zenith cal. 135 •Movement type: Manual winding •Chronometer: Yes •Service history: Fully serviced •Strap: Blue NATO strap •Box: None •Papers: None •Warranty: 12-month service warranty