Watch cases, though fundamentally adhering to the form-follows-function recipe, are as expressive of a timepiece’s identity as is the dial. Think of the bulge on the side of a Greubel Forsey, the U-shape of an Urwerk or the unique and iconoclastic case of the Hamilton Ventura. Tool watches naturally feature robust housings designed to protect the movement against whatever the specific tasks throw up as challenges. Whatever the role, everything about a case serves the manufacturer’s aesthetic dictum.

While the overwhelming majority of watches employ round cases, with square or rectangular types occupying the No. 2 spot, the quiet sibling bringing up third place is the tonneau. Round is always round, varying according to whether or not it boasts shoulders to protect the crown, and lug shapes can vary according to needs or tastes. Square and rectangular cases by definition have four clearly defined corners, but the term “tonneau” is open to interpretation.

This profile embraces everything from the classic, elongated case with “bulging sides” – the most obvious form worthy of the name – to the more squat “barrel” version, to square or rectangular shapes with rounded corners, the latter forming the subdivision called “cushions.” Add the “tortue,” French for “tortoise,” and you have suddenly embraced everything from the Seiko Pogue and various Turtles to the Vacheron Constantin “cioccolatone” to the Panerai Radiomir.

Vacheron Constantin Triple Calendar ‘Cioccolatone’ in pink gold. Image: Phillips
Vacheron Constantin Triple Calendar ‘Cioccolatone’ in pink gold (Image: Phillips)

Accepted lore suggests that the classic tonneau was first devised to adorn ladies’ wrists, but any case designer will tell you that watch comfort (strap and bracelet notwithstanding) depends entirely on the size of the watch relative to the wrist. The shape only interferes if it is too large, e.g. a Heuer Monaco on a tiny wrist, so that explanation doesn’t work. All that the tonneau and its assorted derivatives added to the watch case design language was visual grace, because they certainly didn’t provide stronger case integrity a century ago, and certainly not before the likes of Richard Mille adapted the form to incorporate bomb-proof construction and materials.

More likely, the tonneau was devised as an alternative to the default foundation of early wristwatches – converted pocket watches with soldered-on wire lugs. Even the smallest were large-ish, and the conversions were far from elegant. The tonneau would present a complete departure from the pocket watches that wristwatches were intended to supplant.

Also swiftly discovered back in the early days of the serially produced wristwatch was that larger timepieces sat more comfortably when the cases were curved, as seen from the side view, because this would conform better to the shape of the wrist. This worked beautifully with elongated tonneau cases, and many of the most coveted watches from the 1920s were extremely curved tonneaus. One might also say that, as their peak period coincided with the age of Art Deco, they exemplify that period.

By the late 1920s and early 1930s as automobiles became more accessible, curved tonneau watches from the likes of Mido and Gruen formed a new sub-genre called “driving watches.” They were so named because they fit nicely on the side or back of the wrist, and thus could be read by the driver without any need for him or her to remove a hand from the steering wheel, or twist a wrist toward the eye.

Gruen Curvex driver’s watch (circa 1937), curved for wearing on the side of the wrist for easy time reading while driving (Image: Kalmar Antiques)
Gruen Curvex driver’s watch (circa 1937), curved for wearing on the side of the wrist for easy time reading while driving (Image: Kalmar Antiques)

After a fallow period following the heyday of the tonneau during the early years of the wristwatch and up to WWII, round and square watches grew to dominate timepiece design to the point where the earlier elongated tonneaus and the now-legendary cushion models of the 1950s seemed anachronistic even then. As a result, the 1960s and 1970s were all-but-tonneau-less.

Fast-forward to the early 1990s and the rebirth of the mechanical wristwatch changed all that: Franck Muller’s much-coveted, hugely-popular Casablanca unashamedly revived the tonneau shape, to immediate acclaim. At the dawn of the 21st Century, Richard Mille graced the tonneau with a new attitude and limitless desirability. The rest, as they say, is history.

10 Noteworthy Tonneau Case Watches

Cartier Tonneau, 1906
Cartier Tonneau, 1906

As early as 1906/7, Cartier was experimenting with shapes and dimensions, giving us what many consider to be the most elegant tonneau of them all, the Cintrée. This watch has served as perpetual member of the family right up to the present, over the years appearing in every precious metal, in myriad sizes, with or without diamond encrustation, and even with two dials as the Dual-Time. A typical vintage example, from 1915 and called the Tonneau Cintrée á pattes model, measured 26.2mm wide and 45mm in overall length, while more recently it appeared in the Collection Privée.

Audemars Piguet Carnegie, 1927
Audemars Piguet Carnegie, 1927

Enjoying a renaissance in vintage circles is a tonneau that accomplishes two things: it reinforces the argument that the tonneau was designed for ladies, and it spans the century. Audemars Piguet’s classic tonneau first appeared in 1927 with a 17-jewel movement in an exquisite, elongated case measuring 23.2mm wide and 31.4mm long, and a mere 7.3mm thick. AP’s 18k white gold example in its museum bears applied Breguet numerals. Jump to 1994 and its 25.1mm wide, 34mm long grand-daughter appeared as the Carnegie, in a variety of materials.

Franck Muller Original Casablanca, Salmon-Pink-Dial Version, 1992
Franck Muller Original Casablanca, Salmon-Pink-Dial Version , 1992

Although not a name that rolls off every tongue of late, those who recall the Great Watch Revival will tell you that one of the key players was Franck Muller. When his brand was launched in 1992, he virtually created the concept of the “auteur” watchmaker, and one of the most popular models was the stunning Casablanca. It was enough that here was a hot, new watch in a tonneau case. What made it a stand-out for bon vivants from Munich to Milano to Miami was its most popular dial colour: salmon pink. Offered in both men’s and ladies sizes, it defined the brand… and the era.

Hamilton W10 Barrel shaped Military Watch, 1973 – 1976
Hamilton W10 Barrel shaped Military Watch

Not all tonneau watches were designed for day or dress wear, or, for that matter, civilians. Hamilton’s W10 was a military watch produced for the British army in the 1970s – CWC also offered a similar model – and the good news is they are plentiful and nowhere near as costly as the “Dirty Dozen” time-only military watches that preceded them. Not all W10s are tonneau-shaped, being instead round and conventional, but the tonneaus ironically add a whiff of modernity. As for fooling the eye, the round, rather than case-matching shape of the crystal lessens the tonneau effect, but a tonneau it remains.

Omega Museum Collection, 2005 (Based on 1915 watch)
Omega Museum Collection

Demonstrating the timelessness of the tonneau with a reissue, Omega’s fourth model in its Museum series was a modern edition of the 1915. It was a limited run of only 1915 pieces, but – like others in the Museum collection – can be found from time to time in auction. This 2005 re-edition featured a 43x32mm 18k rose gold case, cream dial an automatic movement and a dial with Art Deco numerals reminiscent of sister brand Longines’ early pieces.

Longines “Art Deco” Tonneau, 1920s
Longines “Art Deco” Tonneau, 1920s

Among the most prolific of the great houses — most people have no bloody idea what an illustrious history is possessed by this maker — Longines produced all manner of tonneau watches, including those with more decorative, less conservative dials and numerals, as well as all sizes. Among the most notable was a model from the 1920s measuring 31mm wide and 50mm long, made wearable by its articulated lugs. If you fancy a vintage tonneau, look no further as Longines remains the most ludicrously under-appreciated manufacture of them all.

Patek Philippe Gondolo, 1993
Patek Philippe Gondolo, 1993

With as long, rich and illustrious a history as Patek Philippe’s, a manufacture with a penchant for adventurous case shapes such is its asymmetric models, it comes as no surprise that one source suggest that the Geneva powerhouse produced a stunning tonneau as early as 1908. What has been authenticated by the company and recorded in the definitive 5-volume study produced by the museum is the Gondolo of circa 1915, made in conjunction with Patek’s long-serving Brazilian importer. With classic tonneau proportions, it lives on to this day as Ref. 7099 in the Gondolo Collection.

Parmigiani Fleurier Kalpa, 2001
Parmigiani Fleurier Kalpa, 2001

Among the new houses — post-1990, that is — Parmigiani Fleurier is probably the most steeped in tradition due to Michel Parmigiani’s background as a restorer and historian. One of the manufacture’s defining collections is the Kalpa line, which comprises just about every precious metal, size and complication one could hope to acquire, but in a gorgeous refinement of the tonneau. To make the shape its own, Parmigiani Fleurier has added lugs that rise above the height of the case, adding a look of strength without sacrificing refinement or delicacy — even in the women’s Kalpa Donna models.

Vacheron Constantin Curved Tonneau, 1920s and 1930s
Vacheron Constantin Curved Tonneau

Like Longines, Patek Philippe and Audemars Piguet, Vacheron Constantin was there at the beginning of the wristwatch’s existence, and — in the spirit of the 1920s — produced elongated, but discreet tonneaus. Their models were less exaggerated in their proportions, leaner rather than wider at the middle. The classic tonneaus from this house are now highly sought after, but the company never abandoned the shape. You can acquire contemporary Vacheron Constantin tonneaus in such timepieces as Les Historiques 1912, various Malte models and the elegant ladies’ Egerie collection.

Richard Mille RM 001 Tourbillon, 2001
Richard Mille RM 001 Tourbillon

If any contemporary brand has embraced the tonneau as a vibrant, living form rather than an exercise in retro, it is Richard Mille – after all, the brand has yet to pass its 20th anniversary, so it has no past to exploit. From the outset, the company has championed the use of extreme materials, robust construction and absolute modernity, and it has forced the tonneau shape to evolve into something truly futuristic. Used across the range, the RM tonneau shape has become the brand’s signature look, overshadowing its round and rectangular siblings.