Zenith
El Primero 21 DEFY BIVER Limited Edition - Full-set 21 ex Signed

Zenith DEFY El Primero 21 reference 95.9010.9004/79.R595, special edition produced in 21 examples according to its original documentation and bearing the signature of Jean-Claude Biver, 44 mm titanium case, fully openworked dial revealing the movement architecture, applied luminous markers and hands, anti-reflective sapphire crystal, transparent sapphire caseback, original rubber strap with titanium folding clasp, mechanical 1/100th-second chronograph whose central hand completes one full revolution every second, 30-minute counter at 3 o’clock, 60-second counter at 6 o’clock, small seconds at 9 o’clock, chronograph power-reserve indicator at 12 o’clock, manufacture Zenith El Primero 9004 chronometer-certified automatic movement, two independent regulating organs and escapements operating respectively at 36,000 vibrations per hour for timekeeping and 360,000 vibrations per hour for the chronograph, 53 jewels, approximately 50-hour power reserve for the watch and approximately 50-minute chronograph autonomy, 100-metre water resistance, 2019 Full Set watch sold pre-owned by Mostra, fully inspected, authenticated and covered by a 3-year warranty.  

The Zenith DEFY El Primero 21 does more than add a spectacular function to one of the most famous chronographs in history. It takes the El Primero heritage, extends it to the hundredth of a second and exposes it fully to the eye, as though the dial had been opened so that the collector could enter the mechanics rather than simply consult them. Its identity is not created by a conventional dial placed above the movement. Here, the watch begins where the dial disappears. Bridges, wheels, regulating organs, counters and the different depths of the calibre create a moving architecture in which every indication finds its place without concealing the mechanism. The eye never settles upon a uniform surface. It moves, discovers a gear, follows a hand, becomes lost for a moment inside the movement, then returns to the time.The 44 mm titanium case gives this architecture the room it requires. Its diameter asserts the presence of the watch, while titanium considerably reduces the sensation of weight on the wrist. The angular case, integrated pushers and alternating brushed and polished surfaces give the whole a technical, almost aeronautical character without turning the watch into a brutal object. The DEFY 21 is substantial through design, far less so through the way it wears.

This lightness becomes a genuine advantage in use. A mechanical watch of such complexity could quickly become tiring if the case added excessive weight to its volume. Titanium instead allows the watch to remain on the wrist throughout a working day, a journey or a weekend without turning its spectacular architecture into a constraint. The rubber strap extends that suppleness, while the titanium folding clasp secures the watch and distributes its weight coherently.

The spectacle truly begins when the chronograph is activated.

The central chronograph hand does not cross the dial in sixty seconds as it would on a conventional watch. It completes an entire revolution every second. When released, it seems almost to tear itself away from stillness, crosses the hundred peripheral divisions and returns to its starting point at a speed the eye must learn to follow. Each graduation represents one hundredth of a second. The measurement is no longer concealed within a difficult display; it becomes visible, immediate and almost physical. This rotation completely changes the relationship with the chronograph. The function is no longer started only to measure a useful duration. It is also started to observe the movement accelerating. The pusher releases energy, the hand launches forward and the watch instantly changes rhythm. This simple gesture remains one of the most striking experiences offered by a contemporary mechanical chronograph.

This performance relies upon an exceptional architecture. The El Primero 9004 calibre uses two distinct systems: a first regulating organ operates at 5 Hz, or 36,000 vibrations per hour, for the hours, minutes and small seconds; a second reaches 50 Hz, or 360,000 vibrations per hour, enabling hundredth-of-a-second measurement. The chronograph therefore does not disturb the regulating organ responsible for timekeeping. It has its own gear train, escapement and source of energy.   This separation is one of the great strengths of the movement. On a traditional chronograph, engaging the function adds a load to the principal mechanism and may influence amplitude. On the DEFY 21, both systems work side by side without depending upon one another. The watch continues to display time at high frequency while the chronograph accelerates within another mechanical dimension. Chronograph autonomy is displayed at 12 o’clock. Its independent barrel provides approximately fifty minutes of operation, deliberately separated from the approximately 50-hour power reserve dedicated to timekeeping. Even the winding process reflects this dual architecture: the rotor maintains the watch barrel, while the crown separately charges the chronograph. The movement does more than display two rhythms; it organises two energy reserves within the same calibre.  

The 60-second counter at 6 o’clock, 30-minute counter at 3 o’clock and small seconds at 9 o’clock provide familiar references within this unusual speed. The display remains complex but never gratuitous. Each counter has a precise purpose, while the coloured accents inherited from the El Primero universe help distinguish the indications through the depth of the openworked dial. The history behind this watch began in 1969. That year, Zenith unveiled the El Primero, one of the first integrated automatic chronographs and the first series-produced movement to operate at the high frequency of 36,000 vibrations per hour. Fifty years later, in 2019, the Manufacture celebrated this heritage by placing the DEFY El Primero 21 beside an A386 revival and a Chronomaster in its anniversary set: past, evolution and future united around high frequency.   This 2019 Full Set edition therefore appeared at a highly symbolic moment. It was produced during the fiftieth anniversary year of the El Primero, yet it did not look only toward 1969. It showed what that historical frequency could become half a century later when a manufacture chose not merely to reproduce it, but to multiply it by ten for the chronograph function.

This is where the presence of Jean-Claude Biver becomes especially meaningful.

When Jean-Claude Biver became involved with Zenith, he rejected the idea of a manufacture condemned to repeat its past indefinitely. His formula was clear: Zenith had to become “the future of tradition.” In his reading, the 1/100th-second chronograph was not a rupture with El Primero; it was its logical continuation, a way of allowing heritage to evolve rather than locking it inside a museum. The DEFY 21 became one of the most visible expressions of that strategy.   The Jean-Claude Biver signature carried by this edition is therefore more than an autograph added to an already rare watch. It directly connects the piece with the man who defended this new interpretation of Zenith, associated the El Primero name with a contemporary architecture and sought to make high frequency not merely a historical chapter, but a platform for innovation. A signature possesses horological value only when it brings context. Here it accompanies a watch embodying one of Biver’s central ideas: take an established legitimacy, respect it, then project it into a form the previous era could not have produced. The hundredth-second chronograph, openworked dial, titanium and DEFY design do not deny the El Primero. They reveal what that history could still contain.

Production limited to only 21 examples considerably strengthens this reading. The number directly echoes the DEFY 21 name and places the series within a form of rarity very different from editions produced in several hundred pieces. Twenty-one watches represent an almost private distribution, sufficiently confidential for every example to retain an identifiable place within the history of this signed series. For the collector, rarity is nevertheless only part of the interest. A watch produced in very small numbers becomes important only when it possesses true coherence. This Zenith combines a technically significant reference, an essential year in El Primero history, a signature directly linked with the strategic development of the model and a Full Set preserving the complete context of the piece.

The 2019 Full Set is therefore essential. Box, documents, accessories and the elements recording this edition of 21 pieces are not merely commercial additions. They identify the watch, preserve provenance and maintain the connection between standard reference 95.9010.9004/79.R595 and the particular series signed by Jean-Claude Biver. On such a confidential piece, documentation directly participates in historical value. The openworked dial also offers a particular advantage to the movement collector. Few chronographs make their architecture so directly understandable without opening the case. The balance responsible for timekeeping, the one dedicated to the chronograph, the wheels, bridges and specific reserve become visible from the wrist. The mechanics are no longer merely explained in a specification sheet; they can be observed while operating.

The sapphire caseback completes this reading by revealing the openworked Zenith star-shaped oscillating weight, the bridges and calibre finishing. The watch therefore offers two mechanical faces: the dial side, spectacular and functional, and the back, more traditional in its presentation of an automatic movement. Between them, the titanium case protects a 53-jewel construction whose complexity remains visible without depriving the watch of daily usability. Its 100-metre water resistance gives this high complication welcome versatility. The DEFY 21 is not a dive watch, yet its construction is sufficiently robust to accompany active life, travel, rain and ordinary use with more confidence than a more delicate high-horology chronograph. It can be collected without remaining imprisoned inside its presentation box.

Wearing this Zenith today means choosing a watch whose rarity is not necessarily recognised from across a room. The public first notices the DEFY shape, openworked dial and movement of its chronograph. Only those familiar with the piece subsequently understand its production of 21 examples, Biver signature and 2019 context. This gradual discovery gives the watch a paradoxical discretion: spectacular in mechanics, confidential in history. This example is offered as a Zenith DEFY El Primero 21 reference 95.9010.9004/79.R595, an edition produced in 21 examples and signed by Jean-Claude Biver, accompanied by its 2019 Full Set. The watch has been inspected with particular attention given to calibre 9004, both escapements, operation of the hundredth-second chronograph, energy reserves, pushers, titanium case, openworked dial and coherence of its documentation.

Choosing a Zenith El Primero from Mostra requires a perspective capable of connecting technique, history and provenance. Every watch is examined through more than 40 years of watchmaking experience, with attention given to authenticity, movement, actual condition, accessories and collector interest. This DEFY El Primero 21 comes with a certificate of authenticity and a 3-year Mostra warranty, a strong commitment on a high-frequency chronograph of such complexity. A piece such as this is not chosen only because it measures one hundredth of a second. It is chosen because it brings together within one object the 1969 El Primero, the contemporary vision of Jean-Claude Biver, the fiftieth anniversary of 2019, a series limited to 21 examples and the almost hypnotic experience of a mechanical hand completing one full revolution every second.