The Blancpain Grande Double Sonnerie: The Ultimate Grand Complication in Haute Horlogerie

The grande sonnerie is one of the rarest achievements in watchmaking. Fewer than a handful of brands can build one. Fewer can build one well. And when Blancpain unveiled their version, (the most complicated watch Blancpain has ever produced) they didn't just enter the conversation. They redefined it.

This isn't a complication you buy because you need to know the time. A quartz movement does that better. Grande sonnerie watches exist purely as demonstrations of what's possible when craft pushes past function into art. It's a melody on your wrist, chiming the hours and quarters automatically, built from hundreds of components that must work in perfect harmony.

This guide explains what makes this the ultimate chiming watch, why Blancpain's interpretation matters, and what the movement reveals about where high-end horology is heading.

What Exactly Is a Grande Sonnerie?

This represents the most complex chiming complication in traditional horology. To understand why, you need to understand what it actually does — and why that's so difficult.

A minute repeater chimes the time on demand. You press a pusher, and the chiming mechanism strikes gongs to sound the hours, quarters, and minutes. Impressive, but not nearly the same.

The grande version goes further. It chimes automatically — every hour, every quarter, without any input. In grand sonnerie mode, the piece sounds the hours at each quarter, then adds the quarter chimes. At 3:45, you'd hear three strikes for the hour, then three sequences for the quarters. The petite sonnerie mode simplifies this, chiming only the quarters without repeating the hours. The grande and petite sonnerie functions give collectors flexibility depending on the setting.

The mechanical challenge is immense. The sonnerie mechanism must track time, store enough power to drive both the movement and the striking, coordinate multiple striking components and gongs, and do all of this while remaining small enough to fit on a wrist. These are among the rarest complicated wristwatches ever produced — most major brands have never even attempted one.

Why Is This Grand Complication So Difficult to Build?

Every grand complication presents challenges. Traditional complications like the perpetual calendar must track months of different lengths and leap-year cycles. A flying tourbillon must rotate a cage while maintaining accuracy. But the grande sonnerie mechanism combines mechanical complexity with acoustics in ways that push horology to its absolute limits. Among all watchmaking complications, this stands apart.

Consider the power requirements. A typical automatic piece might run for 48 hours on a full wind. This must power both the timekeeping movement and potentially dozens of chimes per day — each requiring hammers to strike gongs with enough force to produce audible sound. The Blancpain version carries a power reserve of 96 hours specifically to handle this demand, with separate barrels for the movement and the striking mechanism.

Then there's the acoustic challenge. A chiming watch is useless if you can't hear it. But a watch case is too small to amplify sound, and metal doesn't enhance the chime the way a wooden clock case does. Blancpain addressed this with an acoustic membrane integrated into the bezel — amplifying sound transmission to the wearer's ear.

Finally, there's the coordination problem. The mechanism must know exactly what time it is, decide what to chime, execute the strike sequence, and prevent damage from user error — all through purely mechanical means. The safety systems alone required multiple patents.

What Makes the Blancpain Complication Special?

Blancpain began developing their piece in response to a challenge from within. The CEO of Blancpain wanted a grande sonnerie that would represent the absolute pinnacle of the brand's capabilities — not just a technical exercise, but something worthy of the name.

What emerged was Blancpain's Grande Double Sonnerie, powered by the Calibre 15GSQ. Some refer to it as the Blancpain Double Grande Sonnerie, though officially it carries the former name.

The "Double" refers to something unprecedented: the sonnerie features two different melodies. Most pieces in this category offer a single chime sequence. This version provides two distinct musical options — a traditional Westminster chime and a proprietary Blancpain melody. A pusher at 8 o'clock switches between them. No other piece offers this capability.

The movement comprises of 1,053 components, including a flying tourbillon at 6 o'clock and a retrograde perpetual calendar. The calendar displays day of the week, retrograde date, month, and leap-year indication through a combination of subdials and a sweeping hand that resets at the end of each month. Calendar indications use under-lug correctors to maintain the clean dial aesthetic.

Blancpain went beyond mere technical achievement to ensure the piece actually functions as intended. The mechanism includes a magnetic regulator that controls the speed of the striking train, ensuring consistent tempo regardless of remaining power. A silicon balance spring improves accuracy and resistance to magnetic interference. Every component serves the whole.

How Do the Two Different Melodies Work?

This is the melody you know from Big Ben — four notes arranged in a specific pattern that varies with each quarter. It's become synonymous with clock towers and formal timekeeping, and translating it to a wrist presents unique challenges.

In Blancpain's implementation, this requires four gongs of different pitches and four hammer mechanisms to strike them. The four quarters each sound a different portion of the full melody: the first quarter plays four notes, the second plays eight, the third plays twelve, and the fourth quarter plays the complete sixteen-note sequence before the grand strike announces the hour.

The complexity multiplies when you consider the automatic function. At each quarter, the piece must first indicate the hours, then play the appropriate sequence. At 6:45, that means six strikes for the hour followed by twelve notes for the third quarter. The coordination required — mechanically, without electronics — pushes the limits of what traditional horology can achieve.

Blancpain says this option appeals to collectors who appreciate traditional associations with chiming. The alternative Blancpain melody offers something different: a proprietary sequence that distinguishes the piece from anything that came before.

What Does the Calibre 15GSQ Include?

This movement is essentially three highly complicated mechanisms in one: the striking function with a minute repeater, a flying tourbillon, and a retrograde perpetual calendar. Any one of these would qualify as significant. Combined, they represent the summit of watchmaking.

The movement operates at 4Hz (28,800 vibrations per hour) and measures 38.4mm in diameter — large, but necessarily so given what it contains. The mainplate and bridges are finished to the highest standards with bevelled edges, Geneva stripes, and hand-polished surfaces visible through the caseback.

The tourbillon rotates once per minute, visible through an aperture at 6 o'clock. Unlike a traditional tourbillon with an upper bridge, the flying variant is cantilevered from below, offering an unobstructed view of the cage's rotation.

Power comes from two barrels: one dedicated to the going train (timekeeping) and one to the striking train. This separation ensures that demanding strike sequences don't starve the movement of the power needed to keep accurate time.

How Does the Retrograde Perpetual Calendar Function?

Perpetual calendars track the weekday, date, month, and leap-year cycle without requiring manual adjustment — they correctly handle months of 28, 29, 30, and 31 days automatically. The retrograde version turns it into art.

Traditional calendar displays use hands that rotate continuously around subdials. Retrograde displays work differently: the date hand sweeps forward through the month, then snaps back instantly to restart. At the end of February, it returns from 28 or 29; at the end of March, from 31.

The calendar occupies the upper portion of the dial. The weekday appears through an aperture. Month and leap-year cycle share another display. The retrograde arc sweeps across available space, its hand jumping back at midnight on the final day of each month.

Calendar functions require adjustment only once every 400 years, when the Gregorian calendar skips a leap year (as it did in 1900 and will in 2100). For practical purposes, this piece will outlive its owner without needing calendar correction.

What Case Houses This Complicated Wristwatch?

A movement this complicated demands appropriate protection. The Blancpain Grande Double Sonnerie comes in a 47mm case — large by dress watch standards, but essential given the movement's requirements.

The case is available in white gold or red gold, both precious metals that machine well and offer excellent acoustic properties. The caseback features a sapphire crystal for viewing the movement's finishing and the tourbillon's rotation.

The membrane integrated into the bezel deserves particular attention. Chiming pieces must transmit sound from the gongs inside the case to the air outside. Traditional solutions use the caseback or crystal as the resonating surface. Blancpain's approach directs sound toward the wearer's ear rather than away from it. The engineering required a new patent and years of testing.

The face maintains legibility despite everything happening beneath it. Large Roman numerals mark the hours. The retrograde arc occupies the lower half. Calendar displays cluster at 12 o'clock. The tourbillon aperture sits at 6. A reserve indicator helps the owner track remaining autonomy for both functions.

How Does the Regulator Protect the Mechanism?

Complicated mechanical pieces face a problem simpler ones don't: user error can cause damage. Setting the time while a strike sequence is running, or triggering a repeat while the hands pass through a quarter, risks breaking delicate components.

Protection mechanisms address these scenarios through purely mechanical means. The mechanism will not engage if insufficient reserve remains to complete the sequence. The pusher locks out during hand-setting to prevent damage. A silence mode disables automatic striking entirely for situations where sound would be inappropriate.

The magnetic regulator that controls striking speed also contributes to longevity. Traditional approaches use a fly governor — a spinning vane that creates air resistance to slow the striking train. The magnetic approach achieves the same effect without mechanical contact, reducing wear on components that would otherwise degrade over years of use.

Each protection required design, testing, and in many cases patent protection. The Swatch Group's resources — Blancpain operates within this conglomerate — enabled development that smaller independent watchmakers might not afford.

How Many of These Exist?

Rarity is inherent to pieces this complicated. The complexity means slow production, and slow production means few reach collectors.

Blancpain produces approximately two watches per year. Not two hundred. Not twenty. Two. Each one requires months of assembly, regulation, and testing. A friend of Blancpain — a collector close to the brand — once described the waitlist as measured in years, not months.

This production rate explains the pricing: approximately £1.5 million depending on configuration. At that level, comparison shopping becomes irrelevant. Buyers at this tier are purchasing exclusivity, technical achievement, and a relationship with the brand as much as a physical object.

For context, Patek Philippe's references in this category occupy similar territory — extreme rarity, extreme pricing, extreme complexity. The market for these pieces is measured in dozens of collectors globally, people for whom this represents the ultimate expression of what the craft can achieve.

What Does the Flying Tourbillon and Sonnerie Represent?

This exists at the boundary between horology and art. No one needs a piece that plays Big Ben quarters with choice of melody while simultaneously displaying a full calendar and tourbillon. The thing serves no practical purpose beyond demonstrating mastery.

And yet, this is precisely why it matters. Creations like this push the craft forward. The engineering solutions developed for one piece eventually influence others. The acoustic innovations, the magnetic approach, the protection systems — these may appear in more accessible pieces as the technology is refined and scaled.

Digital technology can reproduce the sound of a chime trivially. Only traditional craft can produce it through springs, gears, hammers, and gongs — through human innovation rather than computation.

Blancpain's creation represents where this craft stands today: extraordinary, impractical, and irreplaceable. For the collectors who pursue these pieces, nothing else compares.

Key Takeaways

• This is the most complex chiming category in traditional horology — automatically striking hours and quarters throughout the day.
• Blancpain's version features two melodies: Westminster and a proprietary sequence, switchable via a dedicated control.
• The Calibre 15GSQ combines three major achievements: the striking mechanism with minute repeater, tourbillon, and retrograde perpetual calendar.
• Power reserve of four days comes from four barrels — two for timekeeping, two for striking.
• The sound transmission membrane represents a patented solution to making wrist-sized chimes audible.
• Production is approximately two pieces annually with pricing around £1.5 million.
• Protection systems safeguard the mechanism from user error, including lockouts during setting and low-power conditions.

What draws you to complicated pieces? Is it the technical achievement, the exclusivity, or something else entirely? I'm curious what matters most to collectors following this space.