Loiseau 1f4 Grande Sonnerie Complication : World’s First Dual Automatic Grande Sonnerie Complication Timepiece with Instant Dial Reversibility

Dominique Loiseau, one of the most talented figures of contemporary horology, presents world’s first dual automatic Grande Sonnerie complication timepiece with instant dial reversibility and 32 functions.

A legendary figure working at the summit of complex horology for more than 30 years, Dominique Loiseau has until now been quietly at work creating remarkable timepieces for the major names of watch industry.

Artisan and teacher at the International Museum of Watchmaking in La Chaux-de-Fonds, restorer of collector’s timepieces and automata, he is also the creator of the exceptional pocket watches Renaissance and Capriccio, the Rose des Temps clock, the six Montres de Sables and the Alpha-Omega automaton.

In addition, Dominique Loiseau is the inventor of the famed Blancpain 1735 wristwatch. He is clearly an unequivocal and truly authentic horological inventor of an exceptional level, a master watchmaker who has created timepieces of every type of complexity, either as unique pieces or in highly limited editions.

This new Grande complication timepiece was unveiled at this year’s edition of Basel world watch fair. The event witnessed the world premiere birth of a new brand: Loiseau.

The new timepiece, named 1f4, represents the culmination of a master watchmaker’s lifetime of accumulated knowledge. As one would expect from a master like Dominique Loiseau, his 1f4 brings major new developments and World Premiere patents to the Grande Sonnerie Complication, never before united within this class of timepiece.

The development of the 1f4 Grande Sonnerie Complication began 6 years ago. To date Dominique Loiseau has dedicated a minimum of 15,000 man-hours towards its realization and production. Designed, executed, finished and assembled within the confines of his atelier located by the shores of the Geneva Lake, using his own machines and hand tools, the 1f4 stands at the very pinnacle of Switzerland’s finest hand made watchmaking traditions and carries the proud designation of “Entièrement manufacturé en Suisse” as this is where it is 100% made.

Many ultra-complicated watches created today often suffer from dials that visually overload the user with an excess of information utilizing numerous hands and indicators. This can easily result in a dial becoming cluttered and illegible as well as inelegant in appearance. For this reason a leading concept that guided Dominique Loiseau during the visual design stage of the 1f4 was to integrate the highest possible number of useful complications onto two separate dials, each of them having its own specific group of complications as well as different characters.

In essence this meant going into uncharted territory with a new approach towards the creation and design of a hitherto unknown and exceptionally complex movement. The sophisticated clarity of the dial layout on each side of the watch is not the result of simply matching two different movements together. Instead, it requires an extremely high level of integration totaling more than 891 discrete parts occupying different layers on both sides of a central base plate. This new layout concept allows the movement thickness to be kept to a minimum and additionally increases many aspects of the movement’s stability.

The first step in the execution of this elegant solution necessitated the development of a World Premiere patent comprising a totally invisible and secret system allowing the watchcase to be completely reversed within seconds, yet requiring no hinges, brackets, frames or any other visually unaesthetic methods to achieve this goal. Even to the initiated, a close inspection of the watchcase of the 1f4 gives nothing away about this mechanical secret that is quietly contained within its case design.

The challenge was to create an exceptionally slim dual automatic Grande Sonnerie Complication. This ingenious system allows the owner of the watch to make full use of all information the 1f4 offers on its elegantly laid out dials showing more than 32 different complications in total. Indeed, one can truly say that the 1f4 represents a landmark for users with the simplicity it brings to complicated watch design on every level, with one dial directed by the split seconds chronograph, the other by the perpetual calendar. Both of these unified horological manifestations are governed by a Flying Tourbillon beating at 21,600 vph as the heart of the Grande Sonnerie Complication movement.

As all connoisseurs will undoubtedly know, the Grande Sonnerie remains unequivocally the most rare and exceptional expression of the watchmaker’s art. Yet rarer is the Grande Sonnerie with an automatic winding system. Nonetheless, the greatest horological, mechanical rarity today is a Grande Sonnerie Complication with a double automatic system utilizing two annular rotors, the only one of its kind in the world, represented by the 1f4, with its total thickness less than 16.64 mm.

Automatic winding systems are absolutely essential to the creation of a beautiful and useful Grande Sonnerie Complication; it is even more important when there are additional complicated functions added to the timekeeping properties of the watch. For example, the Sonnerie, when set to chime automatically in Grande Sonnerie mode, requires vast amounts of energy from the movement. In addition, the energy requirements of the basic functions of the movement need to be respected to insure perfect chronometric results; the same applies to the energy requirements of the other complications the 1f4 Grande Sonnerie Complication offers, such as the split seconds chronograph and the perpetual calendar.

The solution to the problem is not simply the addition of an automatic rotor to the Grande Sonnerie movement; this would result in the watch being far too thick for comfort and would still not solve the issue of energy supply for the other functions the 1f4 movement must fulfill in addition to the Grande Sonnerie.

Conversely, this means the addition of two rotors is normally speaking totally out of the question. On a mechanical level however, this remains the only feasible and realistic solution for the creation of a truly functional and unusable complication timepiece of this type.

Dominique Loiseau’ s unique and also patented system places the dual automatic rotors on the outside of the movement, communicating with the movement via an annular-geared ring with internally placed teeth. These internal teeth communicate with a specially designed pinion at the edge of the movement, thus transferring their energy to the winding barrels. In this manner, the entire rotor mechanism does not add thickness of the watch’s movement, keeping the timepiece itself to an astounding 16.64 mm overall, a World Premiere feat of mechanical magic.

Subtle balance between classicism and modernism, the finely proportioned exterior of the 1f4 displays its sturdy character and reminds us of the source of its own name: the famous Henry Edward Bird chess opening.

When asked what chess and Haute Horlogerie have in common, Dominique Loiseau always enjoys explaining all about the creation and development of a complicated mechanism: starting it right from the first move – the famous opening – while having in mind the goal to reach, the experience in specific strategies, the capacity to apply instant tactics against sudden and unexpected difficulties, being creative at all time! In other words, creating and developing the complex movements of a Grande Sonnerie Complication can be paralleled to chess: a mastermind’s game.

The King, the Queen, the Knight and the other 3 pawns of a chess play are evidently the visible and mobile players of the 1f4.

The phenomenal creativity and care that have been brought to the conception of its movement, allowing the 32 functions to be intelligently and logically spread over its 2 dials, brings this 1f4 into a new dimension in wearing and using a complex master timepiece on a daily base.

Its perfect wrist comfort fit has been made possible thanks to the exceptional dimensions of such a fully automatic Grande Sonnerie Complication: thinness of 16.64 mm and a diameter of 45.2 mm.

The complexity of this rare timepiece, made by hand in the Loiseau ateliers, the care brought to its construction and quality in each of its just less than 1,000 pieces in a whole, is such that only 2 units can be produced every year. Each one of them will be stamped with a unique reference combining its vintage year – the year it will be delivered – and its owner 3 digits monogram or lucky number.

According to each collector’s desire the 1f4 can be crafted in solid 990 Platinum or solid 18K yellow, red (5N) or white gold.

Technical details

– Created from 18K white, yellow or red (5N) gold or Platinum 990.
– Two instantly, secretly and fully reversible dials (World Premiere).
– Case thickness less than 16.64 mm.
– Case diameter 45.20 mm.
– Water resistance 3 ATM (30 meters).
– 4 push-pieces, 4 correctors and 2 crowns.

1. Two instantly, secretly and fully reversible dials (World Premiere).
2. Self-winding movement with annular-geared oscillating rotor (World Premiere).
3. Self-winding striking mechanism with annular-geared oscillating rotor (World Premiere).
4. 60 second Flying Tourbillon.
5. Day/night indicator via a special reflector below the tourbillion cage.
6. Mono pusher split second’s chronograph.
7. Stop and return of the split seconds chronograph via a separate push-piece.
8. 30-minute chronograph counter.
9. Local time hours.
10. Local time minutes.
11. Seconds on the tourbillion carriage.
12. 2nd time zone hours.
13. 2nd time zone minutes.
14. Equation of time.
15. Striking mechanism power reserve indicator on the « Classical » dial.
16. Striking mechanism power reserve indicator on the « Skeleton » dial.
17. Silence.
18. Automatic quarters striking mechanism (Petite Sonnerie au passage).
19. Automatic hours and quarters striking mechanism (Grande Sonnerie au passage).
20. Silence, Petite Sonnerie or Grande Sonnerie selection thru a single push-piece (World Premiere).
21. Minute Repeater (hours, quarters and minutes).
22. Perpetual calendar.
23. Leap years.
24. Day of the week.
25. Month of the year.
26. Date.
27. Moonphase.
28. Perpetual Calendar indications synchronously corrected through the crown (Patented).
29. Day of the week individual correction thru specific integrated corrector.
30. Month of the year individual correction thru specific integrated corrector.
31. Date individual correction thru specific integrated corrector.
32. Moon phase individual correction thru specific integrated corrector.

Movement details
Movement base plate and bridges created from solid 18k white, yellow or red (5N) gold.
– Breguet over coil balance spring.
– Free sprung balance with weight adjustment.
– Movement frequency of 21,600 vph.
– Split chronograph lever with special profile to reduce friction.
– Squared section gong crafted directly from one piece.
– Chronograph functions governed by column-wheel.
– 18K white, yellow or red (5N) gold annular oscillating rotors.
– Movement handmade and finished of more than 891 parts.
– Movement diameter 41.50 mm.
– Movement thickness from hands to hands 14.8 mm.
– Movement thickness from dial to dial 13.0 mm.

Classical Dial
– Created from 18K gold.
– 7 hands.
– Local hours and minutes.
– Moonphase indicator.
– Leap year.
– Month of the year.
– Day of the week.
– Date.
– Power reserve indicator for the striking mechanism.

Skeleton Dial
– Created from 18K gold.
– 9 hands.
– Local time sub-dial with hours and minutes hands.
– Seconds via peripheral markers and the Tourbillon cage
– Second time zone hour and minute sub dial (GMT).
– Day/night indicator via a special reflector below the tourbillion cage.
– 30-minute chronograph counter.
– Equation of time indicator.
– Split seconds chronograph.
– Power reserve indicator for the striking mechanism.

– Created from 18K gold.
-Total number of 16.

– Bracelet attachment with integrated push-piece bar, requiring no special tools (Patented).
– Alligator.

– Created from 18K white, yellow or red (5N) gold or Platinum 990.
– Deployments buckle (choice of 2 or 3 sections) with ‘Comfort Stake System’ (Patented).


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