The most visible action of a chiming watch, where each hammer strikes its corresponding gong, appears rather simple until we consider how the motion of the hands is converted into the correct sequence of strikes. The mechanism responsible for this, along with the quest for the perfect sound, has made chiming complications the pinnacle of complications. So much so that, in a time when perpetual calendars, tourbillons and even rattrapante chronographs have been successfully realized on larger production scales, the construction, assembly and adjustment of a full sonnerie or repeating watch remains a necessarily laborious undertaking, demanding not only a good eye and a steady hand but also a trained ear.

Before the advent of electricity and luminous materials, repeating watches were developed to provide timekeeping in the dark. The earliest repeating watches originated in England. The first was said to be invented around 1676 by Edward Barlow, a clergyman who sought a patent for his invention but was ultimately beaten by Daniel Quare, a clockmaker from London. Quare, with the support of the Clockmakers’ Company, had petitioned King James II to delay the patent grant until his watch could be reviewed by the council. Quare’s design, much like modern-day repeaters, required only a single push piece to activate the strikes and was eventually granted the first patent in 1687. Initial repeating watches were quarter repeaters, designed to chime the hours and quarters. Over time, these evolved into more sophisticated mechanisms, culminating in the minute repeater, which first appeared in Germany around 1720.

It was Abraham-Louis Breguet who made significant advancements in this field. Prior to Breguet’s invention, repeating watches were bulky as they struck time on bells which occupied a great deal of space. The alternative to that was the à toc, also known as a dumb repeater in which a hammer strikes directly on the case to produce thuds so time could be felt. Breguet invented wire steel gongs in 1783, which could be installed along the periphery of the movement, enabling cases to be slimmer. The first minute repeater wristwatch was produced in 1892 by Audemars Piguet at the behest of Louis Brandt & Frère.

Chiming mechanisms are undoubtedly the most fascinating and complex in watchmaking, making that of a perpetual calendar and chronograph look like child’s play in comparison. Today, there are generally two categories of chiming watches: the sonnerie, which chimes the time in passing, meaning automatically, and the repeater, which chimes on demand when activated arbitrarily by a pusher or a slide that projects from the caseband.

Despite various efforts to create more affordable chiming watches, most recently, the impressive Christopher Ward C1 Bel Canto which chimes the new hour in passing, full minute repeating or grande sonnerie watches have remained resistant to democratization due to the immutable manhours involved.

Literature on repeaters is often written for those already familiar to some degree with the art, making it challenging for laypeople to follow. What I have found to be a genuine aid in visualization is to understand how the going train of the watch, the striking mechanism and repeater gear train are connected.

Striking Mechanism

A chronograph mechanism is linked to the going train by means of the fourth wheel whereby an extension wheel is added on top of it to drive the coupling wheel. A perpetual calendar mechanism, on the other hand, is linked to the going train by means of the 12-hour wheel in the motion works, making it, as opposed to a chronograph, a dial-side complication. A minute repeater or grande sonnerie is also a dial-side complication as the striking mechanism is connected to the going train of the watch by having both its quarter and minute snails fixed to the cannon pinion shank, forming the only point of connection. In a chiming mechanism, snails are cam-like components with steps corresponding to the number of hours, quarters or minutes to be struck.

However, unlike a perpetual calendar where its mechanical components are aligned to and directly drives calendar displays on the dial, a chiming watch does not have indicator hands beyond the time and thus allows for some variety in construction. For instance, the striking mechanism can be relocated from bottom to the top plate (bridge side) of the movement when desired. This is done by extending the cannon pinion and attaching the quarter and minute snails before the hour wheel. With the chiming mechanism located on the bridge side, the hammers and gongs can, in turn, be exhibited on the dial. This construction offers the best of everything — the striking can be observed on the dial while the sound generated by gongs can travel forward towards the wearer and the complex striking mechanism is visible on the back. A handful of watches feature such a construction, including the Greubel Forsey Grande Sonnerie, the Carl F. Bucherer Manero Minute Repeater Symphony, the Bulgari Octo Roma Carillon Tourbillon and the recent Hermès Arceau Duc Attelé.

In a watch that combines both a perpetual calendar and a minute repeater in a traditional manner, the minute repeater mechanism remains on the bottom plate (dial side) of the movement, while the perpetual calendar is assembled on a separate plate that is screwed to the movement over the striking mechanism under the dial.

The quarter snail is fitted onto the cannon pinion shank and rotates once per hour. It has four steps corresponding to the four quarters. The minute snail is rigidly fixed to the cannon pinion and has the most peculiar shape with four curved arms, each consisting of 15 steps for chiming 0 to 14 within each quarter, with the step closest to the center of the snail corresponding to 14. To ensure that no minutes will be struck at the 15th minute (a full quarter), or between the completion of an hour and a minute, a retractable cam called a “surprise” is used to extend the support for the feeler at its extremity to ensure it senses “0.” This is necessary as the minute snail is constantly rotating. The surprise piece is named for its sudden action. It remains hidden until it is needed, specifically at the 15th minute. At this point, it snaps forward quickly to extend the zero step and prevents the minute feeler from falling back onto the other steps when no minutes should be struck. The surprise piece is controlled by a flirt and a spring and its movement is limited by a pin on the minute snail. To reduce wear, some minute repeaters have an isolator lever that holds the flirt away from the surprise until the repeater is activated.

In a quarter repeater, a surprise piece associated with the quarter snail is used to keep the quarter feeler on the highest step of the quarter snail when no quarters should be struck.

This would immediately suggest that a quarter surprise should be present in a minute repeater as well. However, it is glaringly absent in every wristwatch minute repeater mechanism you see. Admittedly, this has driven me almost to the point madness until Mathieu Cleguer, a talented independent movement constructor, explained in a voice note that in reality, the quarter snail is the surprise. This is because the quarter snail is pivotably fitted to the cannon pinion. The minute surprise and the quarter snail are attached together but are loose. As such, when the minute surprise is activated, it also moves the quarter snail forward to extend it. At the top of the hour, both the minute surprise and the quarter snail will snap forward to keep their respective feelers at the zero step.

At each turn of the cannon pinion, a pin on the quarter snail advances the tooth of a 12-hour star wheel that is fixed to an hour snail with 12 steps. The quarter, minute and hour snails control the travel of their respective racks, and consequently the number of strikes. In a decimal minute repeater, the snail for the minutes has six arms with 10 steps that encodes 0 to 9 minutes, and the quarter snail is replaced by a tens of minutes snail that has six steps for 0 to 5. They act with racks that have the same number of teeth to produce the strikes. The first decimal repeater in watchmaking was introduced by Kari Voutilainen and they remain exceptionally rare. Other examples include the Seiko Credor Minute Repeater, Jacob & Co. Twin Turbo Furious, Lange Zeitwerk Minute Repeater, and the Panerai Radiomir 1940 Minute Repeater Carillon Tourbillon GMT.

In contrast to a perpetual calendar or a chronograph, significant power is needed to cause two hammers to strike the gongs repeatedly. If power was to be drawn from the movement’s primary mainspring barrel, there will be a significant drop in amplitude. Thus, both minute repeaters and grande sonneries have an independent mainspring barrel as well as a gear train to control the speed of the barrel. In a grande sonnerie, the dedicated barrel is wound via the crown to ensure it stores enough power for automatic striking, but in a minute repeater, it is wound for each activation of the chimes by pushing a slide. Two things happen when the slide is cocked: the barrel is wound, and the striking mechanism is released. The next thing to understand is how the striking mechanism is connected to the repeater gear train.

Repeater Gear Train

The repeater gear train is typically located on the underside of the top plate and thus won’t be visible. However, you get a rough idea where it lies by locating the repeater barrel, which is traditionally positioned between the hammers. While the snails are constantly driven by the motion works of the watch, it is the repeater barrel that drives the racks back to their resting position when chiming is activated. Hence, the rate of unwinding of the barrel determines the speed of the chimes.

There are four components in the striking mechanism that are squared to the repeater barrel arbor: rack pinion, the hour rack, a finger and a quarter driving pinion (which drives the quarter rack). In addition to the complexity of this assembly, it also represents significant height. Thus, in the pursuit of slimness, watches such as the F.P. Journe Souveraine Minute Repeater have departed from this construction.

Of the four components secured to the barrel, the quarter driving pinion, driven by a finger on the same axis, moves freely while the other three are fixed. When the slide is pushed, a winding rack meshes with the rack pinion, winding the mainspring. The mainspring barrel powers a gear train that consists of two or three strike wheels. As the speed at which the gongs are struck is controlled by barrel, a governor is used at the end of the gear train to regulate the unwinding rate of the barrel.

There are two basic types of governors: the traditional anchor governor and the centrifugal governor. The anchor governor functions just like a lever escapement whereby an escape wheel is locked and unlocked by a pallet. A centrifugal governor, on the other hand, is a fly with two curved arms that are weighted at their tips, and as it rotates, the arms extend outwards against the force of a spring until they come into contact with a fixed inner wall. The resulting friction slows the repeater train. The mass is retracted inward again due to the spring force and later due to the lack of friction, the speed increases again. In contrast to an anchor governor which makes a distinctive buzzing noise, a centrifugal governor is much quieter.

When the slide is cocked, the winding rack winds the mainspring and releases the striking mechanism, causing an hour feeler to fall onto the step of the hour snail, which determines the number of hours to be struck. This hour feeler is attached to the winding rack that winds the barrel. Unlike the quarter and minute racks, which have feelers  integrated into their rim to interact with their respective snails, the rotation of the hour rack is typically controlled by the hour snail without direct interaction. The hour feeler attached to the winding rack contacts the hour snail, which limits the rotation of the barrel and consequently that of the hour rack. Although there were other configurations used historically, deviations from this template are very rare today, with the Chopard L.U.C Full Strike, the F.P. Journe Minute Repeater and Greubel Forsey Grande Sonnerie being notable examples.

While the quarter and minute racks have complicated shapes, the hour rack is a small circular rack with 12 teeth on a section of its circumference, while the other half of it has no teeth to ensure that it will not chime beyond that as it continues to rotate with the barrel. It is screwed to the barrel and rotates anticlockwise as the barrel is wound. Depending on the travel of the hour rack, some of its teeth would move past the hour pallet, sometimes referred to as a hammer trip — a small lever with a tooth. It is held in place by a spring and is similar to a winding click. When the racks are cocked, the trips let the teeth pass and when they return to the resting position, the trip engages the teeth. There are four trips in a minute repeater — one for the hour, another for the minutes and two for the quarters.

As the barrel is wound and the hour rack rotates, the finger fixed to the barrel arbor would be rotated by the same angle. A release finger that is screwed to the winding rack then lifts the so-called all-or-nothing spring lever. This piece is named for its function: it ensures the watch strikes only when the repeater mechanism is fully cocked – when the winding rack has moved far enough – thereby preventing incomplete chiming. Once it is lifted, the quarter rack is released unto its snail.

There are two sets of three teeth on the quarter rack — one to drive a smaller quarter hammer trip and the other to drive the larger quarter hammer trip. The two sets of teeth are designed to give each quarter a double strike — ding dang.

The minute rack is driven by a minute driving hook that pivots on the quarter rack, while the minute rack itself pivots on the same axis of the quarter rack. The minute rack has 14 teeth on its upper rim that come into contact with the minute hammer trip. On its lower rim are five (sometimes seven) gathering teeth that meshes with the minute driving hook. As the quarter rack is released, its beak releases the hour hammer trip, and the minute driving hook releases the minute rack onto its snail.

Once the racks have fallen onto their snails and the slide has been released, the watch is ready to strike. As the train runs down, the teeth of the hour rack, rotating clockwise, trip the hour pallet causing the large hammer to rise and fall, striking the hours. At the same time, the quarter rack is driven back to its rest position by the driving pinion screwed to the barrel. The finger fixed to barrel arbour pushes a post on the driving pinion which in turn drives the quarter rack via its internal teeth.

Its two sets of teeth trip the quarter pallets, thereby causing both the large and small hammer to rise and drop, striking the quarters. The quarter rack continues to turn, and the minute driving hook meshes with the minute rack, allowing the small hammer to strike the number of minutes indicated by the minute snail. Both racks will rotate until the quarter rack is locked by the all-or-nothing piece.

There are two gongs of different pitches in a minute repeater. They are screwed to the mainplate by a metal foot, with each encircling the movement in opposite directions. The pivots of the hammers are located right next to the foot on the bridge side of the movement — one on each side of the repeater barrel.

Both the hammers and gongs are made of hardened steel. The larger hammer strikes a low-pitched gong, while the smaller hammer strikes a high-pitched gong. Each hammer is connected to a trip on the underside by a pin which is impulsed by a return spring to allow the hammer to strike the gong.

Chiming Configurations

Today, there are a variety of chiming watches, each offering unique acoustic experiences. Terms like Westminster, carillon and cathedral are commonly used to describe the distinct qualities and complexities of their gongs and hammers.

A Westminster chiming watch features the familiar four-note melody heard in Big Ben, using four gongs and four hammers to create its distinctive sound. Carillon repeaters, on the other hand, include any chiming watch with more than the typical two gongs, allowing for more elaborate melodies beyond the standard hour, quarter hour and minute strikes. Lastly, cathedral repeaters are distinguished by their extended gongs, which are coiled twice around the movement to produce a deeper, more resonant sound, akin to the rich acoustics of a cathedral.

Grande Sonnerie

At the pinnacle of chiming complications is the grande sonnerie which chimes the hours and quarters in passing. It invariably also functions as a minute repeater, chiming the time on demand. Additionally, it always offers a silent mode to prevent automatic striking when not wanted. While the fundamental mechanism remains largely the same as in a minute repeater, several adjustments are required: the chiming barrel must have a longer mainspring for sufficient power, the winding mechanism must be adapted as the barrel has to be wound via the crown, and three additional mechanisms must be added — an automatic release mechanism for the sonnerie, a manual release mechanism for the repeater and a silencer. Hence, a grande sonnerie is much more complex than a minute repeater, typically comprising 600 to 800 parts, while a minute repeater has about 300 to 500 parts, including all-important safety mechanisms.

The first grande sonnerie wristwatch was introduced by Philippe Dufour in 1992, followed by Gérald Genta in 1994. Today, they remain nothing short of mechanical miracles mastered only by the best, wisest and most experienced watchmakers.

Case Materials

While mechanics are absolute, acoustics, as with aesthetics, are highly subjective; some enthusiasts prioritize vibrancy and volume while others prefer warmth and nuance. The best chiming watches strive for both volume and warmth. High-density materials conduct sound waves more efficiently, meaning they can transfer sound with minimal energy loss. However, they tend not to resonate as much. Resonance is the property that can amplify sound by enhancing certain frequencies. This is why musical instruments like guitars and violins use low-density materials like wood for their bodies; the wood resonates with the strings’ vibrations and amplifies the sound. Materials such as titanium and carbon composites resonate more, which can make the chimes more vibrant and dynamic.

Platinum, due to its high density, has a dampening effect, which reduces the amplitude of the sound waves and further contributes to softer and mellower chimes. Rose gold is generally thought to be the most ideal material for a chiming watch, producing a classic traditional sound profile — warm, yet clear and resonant. Rose gold contains more copper compared to yellow gold which contributes to its unique tonal qualities. The presence of copper helps to give the sound a roundedness, while the gold ensures clarity and purity of tone. The specific mixture provides a harmonious balance that is difficult to achieve with other metals.

Case, Hammer & Gong Innovations

The complexity of repeating mechanisms calls for a cautious approach towards innovation. Racks and snails, which form the fundamental components of the strike works, for instance, have remained largely unchanged and are instantly recognizable across various watches. On the other hand, extensive research and development have been devoted to improving the volume and tone of the chimes over the last two decades. This far-from-comprehensive overview highlights some of the most memorable innovations.

In 2005, Jaeger-LeCoultre introduced “crystal” gongs in the Master Minute Repeater, where the gongs were attached to a layer of metal deposited on the underside of the front crystal. This allows sound energy from the gongs to transfer directly to the crystal unhindered, which in turn acts as a more efficient resonator to broadcast the chimes to the outside of the case. Moreover, with the gongs located at the top of the case and sound transmitted through the crystal, the case could be sealed against water ingress, achieving a depth rating of 50 meters — a first in watchmaking. The use of a pusher instead of a slide allows for a more straightforward application of gaskets. At launch, the Master Minute Repeater was one of the loudest repeaters on the market, and its modern descendants remain among the loudest striking watches available today.

Later in 2009, the brand introduced “trebuchet” hammers in the Hybris Mechanica Grande Sonnerie. The hammers are hinged in the middle with a spring fixed within it. This spring stores energy when the hammer is drawn back, just like a medieval siege engine, enabling a more forceful strike.

One of the most significant innovations in terms of volume and sound quality is the Supersonnerie technology by Audemars Piguet, which first made its debut in the Royal Oak Concept RD#1 in 2015. It introduced a resonance membrane — a soundboard sandwiched between the caseback and movement plate — that is made from a copper alloy and on which the gongs are attached. The goal was to produce a chiming wristwatch that would match the output levels of a voluminous pocket watch and, in so doing, allow it to be sealed against water. In addition, the caseback contains a number of small apertures that allow sound to exit the watch. Due to the use of copper, the sound produced is uniquely warm and loud.

The Chopard Full Strike launched in 2016 is another landmark minute repeater. Both the repeating mechanism and the hammers are mounted on the dial side, while the gongs and watch crystal are crafted from a single block of sapphire crystal. The sound generated by the gongs can be transmitted directly forward, projecting it outwards towards the wearer of the watch.

In 2020, Jaeger-LeCoultre debuted a new gong construction in the Master Grande Tradition Répétition Minutes Perpétuelle. It features a pair of blued steel gongs welded together at their bases and then attached to the baseplate with two screws. From the base, the gongs travel in the same direction, rather than opposite as with traditional gongs, and circle around the base of the movement. As they nearly complete the circumference of the movement, the gongs arch dramatically upwards towards the dial and then diverge in opposite directions around it. As such, the blued gongs are visible on both the front and back of the watch. Sound is amplified due to the proximity of the gongs to the surface of the case, avoiding the various snails, racks and governor that would otherwise damper the sound. As such, the watch is rated to 50m as waterproofing the case doesn’t diminish its acoustics.

While Patek Phillippe is generally known for perfecting the art of a traditional minute repeater, the “Advanced Research” Fortissimo Ref. 5750P launched in 2021 represents a significant innovation. It incorporates a sound lever in the shape of a tuning fork mounted on the foot of the gongs that extends to the center of the movement, where it is attached to a thin sapphire disk. This sapphire disk vibrates freely when the gongs are struck. Sound is then distributed through four openings at three, six, nine and 12 o’clock in a titanium movement ring, with the sound waves exiting a narrow slot between the caseback and caseband. To ensure that no parasitic vibrations will be transmitted to the movement, an insulating rim made of a high-tech material (a polymer as suggested by the patent) isolates the foot of the gongs from the rest of the movement. Interestingly, the hammers are made of platinum instead of hardened steel to produce a more sophisticated sound profile — a softer strike without compromising sonority. To demonstrate the advantages of the Fortissimo system, the watch is cased in platinum.

This year, Hermès introduced the Arceau Duc Attelé created in collaboration with Le Cercle des Horlogers in which the gongs take the shape of a tuning fork with elongated U-shaped branches. Despite encircling the movement only once, due to its dual branches, the sound it produces is akin to that of a cathedral repeater, where the gongs encircle the movement nearly twice.

Governor Innovations

Patek Philippe was the first to introduce serially produced minute repeaters with centrifugal governors in 1989. Since then, this mode of regulating the speed of chimes has become a mainstay in watchmaking, though some brands like Audemars Piguet and Breguet still use anchor governors. However, not all centrifugal governors are created equal; only a few are completely silent. While it is quieter than a traditional anchor governor, its spinning arms tend to produce a faint whirring noise of their own as they sweep against the wall of its housing. This calls for systems that don’t rely on solid friction.

In a standard centrifugal governor, centrifugal force causes the weighted arms to spread outward from the center, creating frictional resistance as it touches the inner wall of the housing and slows down the gear train. In contrast, Vacheron Constantin’s flying strike governor employs a more refined mechanism that does not have a housing. As the governor spins, centrifugal force pulls one end of each weight outward, while the other end, influenced by centripetal force, applies pressure towards the axis of rotation and slows down the train.

The governor used in the Credor Spring Drive Minute Repeater/ Sonnerie remains the most interesting and unusual. It relies solely on air viscosity rather than friction to create resistance and is hence completely silent. It consists of two crescent-shaped blade wings and two guiding plates. When assembled, they appear circular in plan view. Each wing has a post on which a zigzag spring is hooked. The other end of the zigzag spring is attached to the guiding plate. Notably, each wing has a finger on its inner end that will contact a post on the guiding plate to limit is movement. The entire governor is located between two plates with a circular cut-out. As its wings expand outside of their guiding plates and into the gap between these two plates, they are subject to greater resistance due to air viscosity and this causes their speed to drop. As their speed decreases, the zigzag spring pulls the wings back in towards the guiding plate.

In addition, as the Spring Drive’s Tri-synchro regulator is totally silent, without the characteristic tick tock found in a regular escapement, it makes for one of the purest sounding chiming watches.

Breguet, on the other hand, has used a magnetic governor in the Classique La Musicale 7800. This design features arms that rotate within a magnetic field created by static magnets positioned around the regulator’s outer edge. As these metal arms spin, they generate an eddy current due to their motion through the magnetic field. The interaction between the electrical field and the magnetic field creates resistance. The faster the arms rotate, the greater the resistance, which slows the rotation. Conversely, when the rotation speed decreases, the resistance diminishes, allowing the arms to speed up. This dynamic balance ensures constant rotation, as any changes in speed are met with an opposing force that stabilizes the rotation. The Omega Chrono Chime similarly relies on a magnetic governor.

Killing the Awkward Silence

One of the more fundamental innovations has to do with improving the quality of strike sequence, namely eliminating the silent interval between the completion of the hours and the start of the quarters and between the completion of the hours and the start of the minutes when there are no quarters to be struck.

This dead time occurs due to how each rack is driven; there is no direct connection between the hour and quarter racks. The hour rack is directly driven by the repeater barrel while the quarter rack is driven by a pinion that moves freely on the repeater barrel arbor. This pinion is in turn driven by a finger fixed to the square of the repeater barrel arbor. Hence, the time taken for the finger to reach a post on the pinion varies. Only the quarter and minute racks are directly connected; the minute rack is driven by a hook pivoted on the quarter rack. However, it typically has five or seven driving teeth. These teeth are quite wide, and the hook’s landing position on their faces can cause slight variations in intervals.

Solutions to this problem began surfacing likely in 2014 with the Jaeger-LeCoultre Hybris Mechanica Eleven and, since then, several other brands, including Audemars Piguet with the Royal Oak Concept Supersonnerie, Chopard with the Full Strike, Greubel Forsey with the Grande Sonnerie and Vacheron Constantin with the Symphonia Grande Sonnerie, have emerged with their own solutions. This typically involves a wholesale revamp of the hour, quarters and minute racks.

In a patent filed by Complitime, a very clever solution is employed. The hour rack (2) was redesigned and it pivots on the same axis (3) as the quarter and minute racks. It is no longer a circular rack and better resembles the other racks, featuring internal teeth (9) on its hollow and is driven by a pinion (10) linked to the repeater train. It has a feeler (12) on one end that directly interacts with the hour snail (13). There is a hook (18) attached near its hollow that allows it to drive the quarter rack (Fig. 3). As such, the quarter rack is designed with three driving teeth (21) — four faces for the four quarters and the hook is able to drive the quarter rack to the right position more accurately.

At the same time, there is a pin (22) fixed to the movement plate that facilitates the release of the quarter rack (4) when the slide is armed. Once the hour rack pivots and falls on its snail, driving the hook, the hook is stopped and lifted by the pin, releasing the quarter rack. When the slide is released, the hour rack pivots around its axis driving the hook, which is no longer retained by the pin and pivots to cooperate with one of the teeth on the quarter rack.

The minute rack (Fig. 4), in turn, has 14 driving teeth (34) instead of the usual five. This increased resolution which corresponds directly to the number of minutes reduces dead time. When striking, the driving hook (30) attached to the quarter rack picks up one of the driving teeth on the minute rack (6).

In the Chopard Full Strike, a similar approach is used. However, the entire repeating mechanism is more complex with a higher part count. It was designed for compactness specifically on the lateral plane as well as to reduce dead time. The trip pins are actuated by ratchet wheels – an hour, quarter and minute ratchet – instead of the racks themselves. The three ratchet wheels are mounted on the same axis and each ratchet is in turn driven by its respective rack which is attached to a feeler. The hour ratchet has four internal steps that corresponds to 0 to 3 quarters while the quarter ratchet has a hook attached to its inner circumference that engages with one of these internal steps. As the hour ratchet advances, the hook on the quarter ratchet catches onto one of the internal steps of the hour ratchet, ensuring it is correctly aligned to chime the quarters without delay. The minute rack, like Complitime’s, has 14 driving teeth that engages with a hook pivoted on the quarter rack.

Repeating Complications

Typically, when a minute repeater is combined with other complications, such as an chronograph and a multi-time zone function, it operates independently. Both complications are not mechanically coupled beyond how each of them is linked to the going train of the watch as explained above. However, over the last decade, several highly sophisticated repeating watches have emerged that integrate complications more productively.

In 2016, a two-time-zone decimal repeater, the Panerai Radiomir 1940 Minute Repeater Carillon Tourbillon GMT PAM 600, became the first repeater of any kind that could chime both home time and local time. Similarly, the Patek Philippe Ref. 5531, unveiled in 2017, was the first worldtime minute repeater that could chime local time instead of home time. As only the hours need to be adjusted to reflect the second time zone, this is done by letting the 24-hour time zone wheel in the worldtime mechanism drive the hour snail while keeping the quarter and minute snails attached to the cannon pinion.

In more recent years, there is the magnificent Omega Chrono Chime, a high frequency 5Hz rattrapante chronograph with a minute repeater that could chime elapsed time in minutes up to 15, tens of seconds and seconds once the chronograph is stopped. It chimes a low note for the minutes, a double high-low note for the tens of seconds and a high note for the seconds.

Instead of attaching the snails to the cannon pinion on the dial side, the snails are attached to the chronograph mechanism. The minute snail has 15 steps to encode 0 to 14 and is attached to the minute recorder wheel. The tens of seconds snail has 6 steps corresponding to 0 to 5 seconds while the seconds snail has six curved arms each with 10 steps to encode 0 to 9 seconds. Both seconds snails are attached to the chronograph main wheel, and as such, the watch will chime the longer elapsed time when if the split was activated.

As the minute snail is far from the pusher, a system of levers is used to traverse the distance and sample the minute snail and transmit this information to the minute rack. The minute rack is squared to an intermediate winding wheel, which is positioned before the repeater barrel. Like the hour snail in a standard minute repeater, the minute snail in the Chrono Chime is circular with teeth only along a section of its circumference. The tens of seconds and seconds racks pivot on the same axis and are driven in a way similar to the quarter and minute racks in a traditional minute repeater. Specifically, the tens of seconds rack is driven by a pinion that is squared to the intermediate wheel and seconds rack is driven by a hook pivoted on the tens of seconds rack. There is a lot more to this movement, including a magnetic governor, but you get the idea of how the strike mechanism is integrated into the chronograph.

Last year, Louis Vuitton unveiled the LVRR-01 Chronographe à Sonnerie in collaboration with Rexhep Rexhepi. Like the Omega Chrono Chime, it combines a chronograph with a chiming mechanism and is able to chime elapsed time. However, it chimes the minutes automatically every minute while the chronograph is running. The construction of the movement is very unusual where the chronograph mechanism is located on the dial side of the movement along with the hammers, while the strike train is beneath the bottom plate. The mainspring barrel is notably large as it has to have sufficient power for 60 strikes. Depressing the chronograph pusher also winds the chiming mainspring which is, in turn, regulated by a traditional anchor governor. The design of strike works can’t be seen but given the placement of the pusher and the hammer, it must be quite unusual, and an automatic release mechanism is needed to release the chiming gear train every minute.

Lastly, there’s the Minute Repeater Alarm ref. 1938P-001 launched to mark the 85th birthday of Philippe Stern this year. It has a 12-hour programmable alarm that strikes the programmed time in hours, quarter and minutes when the time is up. This repeater alarm function first made its debut in the Grandmaster Chime in 2014.

Traditionally, a regular alarm watch is a much simpler mechanism than a minute repeater. The hour wheel is designed with three catches, and an alarm wheel with three openings pivots beneath it when viewed from the dial side. An alarm lever presses the hour wheel against the alarm wheel, which directly drives the alarm disc on the dial and can be rotated via a secondary crown to set the alarm. The alarm barrel is wound via the secondary crown in the neutral position and it drives a strike wheel. This strike wheel acts as an escape wheel, which is locked and unlocked by an anchor. A single hammer is attached to this anchor. When the time is up, the three catches on the hour wheel slips into the three openings of the alarm wheel. The alarm lever tilts and releases the anchor, thereby allowing the hammer to which it is attached to strike.

A minute repeater alarm, however, involves the very same striking mechanism and repeater train as in a regular minute repeater. They are only released by an alarm mechanism when the time displayed on the timepiece corresponds to the alarm time previously set.

In the Grandmaster Chime, the alarm mechanism is activated by a push piece once the alarm time is set. It comprises of a stop cam that acts with a stop lever to control the strike wheel (escape wheel) and a trigger cam that acts with a pusher trigger lever. The stop cam and trigger cam are mounted on the pivot of a trigger wheel linked to the hour wheel. When the push piece is depressed, the racks are released but they are held back from falling onto their snails by the trigger lever which cooperates with retaining pins. When the time is up, the trigger lever and stop lever fall into the notches of their respective cams. The trigger lever frees the racks while the stop lever frees the strike wheel, allowing the hours, quarters and minutes to be struck in a conventional way.

In the Minute Repeater Alarm ref. 1938P-001, it is significantly more complicated. While the same principle applies, a column wheel is used to switch between the different states. Depending on the mode, the slide winds the barrel and releases the striking mechanism to stike the current time or activates the alarm mechanism and puts the strike on hold until the predetermined time is reached.

Chiming watches are a subject of immense reverence due to the complexity involved in their most basic form, and it is impossible to be comprehensive until you’re able to make one. The level of expertise required of both the hand and the ear makes them the highest achievements in horological art, and the owners of these watches take delight in their sonic beauty as much as they relish understanding the behavior of such an inordinate number of parts.