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Lot Essay
Presented in June 2022, the Zenith x Kari Voutilainen Calibre 135-O represents one of the most extraordinary collaborations in modern watchmaking. During a review of its archives, Zenith rediscovered a small number of calibre 135-O movements, the legendary observatory chronometer calibres that had competed in the prestigious Neuchâtel Observatory trials between 1950 and 1954. The suffix 'O' denotes Observatoire, reflecting their exclusive purpose as competition movements rather than commercial products. Conceived specifically for chronometry contests, the calibre was designed around a 30 mm diameter, the maximum permitted for the wristwatch category, and a large 14 mm balance wheel, paired with an oversized barrel to maximise precision, stability, and consistent power delivery.
Manufactured between 1949 and 1962, the calibre 135 existed in two distinct forms: the commercial calibre 135 and the exceptionally rare calibre 135-O, reserved exclusively for observatory competitions. Never intended for sale, the 135-O achieved an unrivalled record of more than 230 chronometry awards, making it the most decorated competition movement in the history of watchmaking. Fitted with Guillaume balances and meticulously regulated by Zenith's celebrated chronométriers, Charles Fleck and René Gygax, the present movement was adjusted by the latter before competing at the 1954 Neuchâtel Observatory trials, where it achieved a First Prize distinction.
Because these movements were built solely as precision instruments, their finishing prioritised performance over aesthetics and they were never intended to be cased as wristwatches. After remaining dormant for more than six decades, each movement underwent an exhaustive restoration under the direction of master watchmaker Kari Voutilainen. Between 2020 and 2022, Voutilainen and his team completely dismantled every calibre, inspected each individual component, restored the original tolerances, and reassembled the movement before applying the exceptional hand-finishing for which the Finnish master is internationally renowned. The result is a remarkable union of one of the greatest chronometry movements ever created with one of contemporary independent watchmaking's finest finishing ateliers.
The present timepiece is further accompanied by a remarkable presentation box inspired by the original wooden storage cases in which these observatory movements had been preserved for decades. Constructed from two wooden halves secured by brass fittings, it pays homage to the movement's extraordinary provenance. Even more significantly, the original historical movement box is supplied alongside the watch, providing an exceptional link to its competition history.
Just eleven calibre 135-O movements were selected for this remarkable project. Of these, only ten were cased in platinum with a black dial, while the eleventh was reserved for a unique charity piece, making the present timepiece one of the rarest and most historically significant contemporary collaborations ever undertaken by Zenith.
Manufactured between 1949 and 1962, the calibre 135 existed in two distinct forms: the commercial calibre 135 and the exceptionally rare calibre 135-O, reserved exclusively for observatory competitions. Never intended for sale, the 135-O achieved an unrivalled record of more than 230 chronometry awards, making it the most decorated competition movement in the history of watchmaking. Fitted with Guillaume balances and meticulously regulated by Zenith's celebrated chronométriers, Charles Fleck and René Gygax, the present movement was adjusted by the latter before competing at the 1954 Neuchâtel Observatory trials, where it achieved a First Prize distinction.
Because these movements were built solely as precision instruments, their finishing prioritised performance over aesthetics and they were never intended to be cased as wristwatches. After remaining dormant for more than six decades, each movement underwent an exhaustive restoration under the direction of master watchmaker Kari Voutilainen. Between 2020 and 2022, Voutilainen and his team completely dismantled every calibre, inspected each individual component, restored the original tolerances, and reassembled the movement before applying the exceptional hand-finishing for which the Finnish master is internationally renowned. The result is a remarkable union of one of the greatest chronometry movements ever created with one of contemporary independent watchmaking's finest finishing ateliers.
The present timepiece is further accompanied by a remarkable presentation box inspired by the original wooden storage cases in which these observatory movements had been preserved for decades. Constructed from two wooden halves secured by brass fittings, it pays homage to the movement's extraordinary provenance. Even more significantly, the original historical movement box is supplied alongside the watch, providing an exceptional link to its competition history.
Just eleven calibre 135-O movements were selected for this remarkable project. Of these, only ten were cased in platinum with a black dial, while the eleventh was reserved for a unique charity piece, making the present timepiece one of the rarest and most historically significant contemporary collaborations ever undertaken by Zenith.