Open heart watches have a hole on the dial showing the balance. It’s part of the romantic side of mechanical watches, comparing the balance with the heart of a human body, constantly spinning back and forth from two and a half to five times per second, bringing the watch to life. I had the pleasure of going to a Swatch Group course on watchmaking, a two-hour session in which participants take apart and reassemble a movement, and there is a step in this process when you take the balance wheel assembly, complete with the spiral balance spring, and place it into position in the movement, and the balance immediately starts operating. It’s a magical moment, and it feels like you are bringing something to life. So I can understand why some brands make open-heart watches in which you get a glimpse of the pulsating balance that in theory could continue running for the entire life-span of the owner, perhaps a couple of days more if the owner had been able to wind the watch just before drawing his or her final breath.

Cheap open heart

A lot of cheap watches have circular windows revealing the balance. Often the hole shows what is actually the underside of the balance assembly, so you see the balance bridge and only glimpse the actual balance itself. Generally you get a better view of the balance through the display caseback, and manufacturers of cheap watches don’t modify the movement in their open-heart timepieces.

Faux tourbillon

In the good old days of watchmaking, the internal workings were always hidden, to increase protection from water, dust and light, all of which have detrimental effects on the movement. Today, mechanical watches are much more than just machines to show the time. They are miniature works of art, and increasingly the display caseback has become an important part of marketing. Most tourbillon watches have a circular window revealing the tourbillon balance. There are many cheap watches in which the open-heart window is designed specifically to give the impression of a tourbillon.

Some brands would never even consider making an open-heart watch. Rolex, for example, have never revealed anything of their movements. In this list of top 10 open-heart watches, the highest-end brand is Zenith – unless you know better, of course. Just leave a comment if I have left out some significant pieces, or send me a photo of your own open-heart watch (info@timetransformed.com – thank you!). The list is in ascending price order.

Stührling Perennial 781 Automatic 42mm Skeleton – €142

On the Stührling website the price of this watch is shown at $165, discounted from a list price of $1,295, but I guess that this is just a bit of cunning marketing. Stührling is a New York-based brand that markets Chinese-made watches, with a huge catalogue and (to judge from their own Facebook page and watch forums) considerable problems regarding quality and after-sales service. Apart from that, the thing that I notice about Stührling watches is that there is always something not quite right in the design, too much decoration for its own sake, features that are borrowed from here or there but that don’t work well together. Brands like Helm and Stoic World work with Chinese suppliers but maintain total control of design and quality control, and you can see the difference. In this Perennial 781, there is a seconds scale surrounding the circular aperture for the balance, a scale that serves a purpose in a tourbillon watch, but that here is just superfluous decoration. The pilot’s watch crown and the lack of proportion in the hands reveal the same lack of bearings when it comes to design. The watch has an automatic movement, visible through the display caseback. On the positive side, the opening on the dial reveals more of the balance than in many other of the open watches described in this article. Read more on the Stührling website.

Zeppelin Flatline 7364-4 – €279

The Flatline by Zeppelin has a 40 mm case, 12 mm thick, and it has dress watch looks except for the open-heart window that reveals the balance. The movement is the self-winding Calibre 82S5 made by Miyota, part of the Japanese Citizen group. It runs at 21,600 vibrations per hour, 3 Hertz, and has a power reserve of 42 hours. See more on the Pointtec website. Price €279.

Ingersoll Hawley Automatic I04605 – €505

The Hawley Automatic I04605 by Ingersoll is an example of the “faux tourbillon” open-heart watch, with a balance bridge imitating the famous complication. The dial is given more complexity by a retrograde date display at top left, and a power reserve indicator at top right. When you look through Ingersoll’s collection you can’t help thinking, why don’t they simplify their watches? This piece would have looked quite good without the minutes scale on the bezel rehaut, without the date, and a more subtle power reserve indicator. It’s fairly large at 44 mm diameter and 15 mm thickness, with leather strap and mineral glass watchglasses front and back. The self-winding movement is undoubtedly Chinese, probably by Sea-Gull or Shanghai. The brand is owned by Zeon Watches, a British subsidiary of the Chinese company Herald Group. The Ingersoll Hawley Automatic costs €505, and it has a lifetime guarantee. Read more on the Ingersoll website.

Tissot Tradition Powermatic 80 Open Heart – €650

The Tradition Powermatic 80 Open Heart by Tissot is a watch with a classical feel and a slim case – just 9.4 mm thick – that is 40 mm in diameter with the standard water resistance of 3 bar. The circular open heart window is centred on the balance but you only get a glimpse, most of the space is taken up by fixed bridge structures. The movement is the Powermatic 80, self-winding and providing 80 hours power reserve. Reference T0639071603800, price €650. More information from the Tissot website.

Claude Bernard Classic Automatic – €665

The elegant, dressy Classic Automatic by Claude Bernard has an ETA 2824-2 or Sellita SW200 movement, with display caseback and 50 metres water resistance. It is 40 mm in diameter and 10 mm thick. It is reference 85017 3 AR and it costs from €665. More information on the Claude Bernard website.

Seiko Premier Novak Djokovic Automatic Limited Edition – €680

This Seiko Premier watch was designed for Novak Djokovic, whose signature appears on the transparent caseback. In addition to the open-heart window revealing the balance, the central section of the dial has a mesh structure that is a reference to a tennis racket. There are two versions, a dressier piece in rose gold with brown strap, and a sportier version in blue. The sports theme continues in the strap, which has a silicone lining under the calfskin leather to improve its comfort, and the water resistance, 10 atm or 100 metres. It is just under 43 mm in diameter and 12 mm in thickness. The 4R71 automatic calibre runs at 3 Hertz, 21,600 vibrations per hour. The blue version is reference SSA375, a limited edition of 3,000 pieces, price €680, available from September 2018. More information from the Seiko website.

Hamilton Jazzmaster Open Heart Auto – €775

In the Jazzmaster Open Heart Auto, quite a lot of the dial is removed to expose parts of the movement, with parts of the balance assembly visible at 12 o’clock. Unusually for Hamilton, there is no date window. The hour and minute hands have a coating of SuperLuminova. The watch also has a display caseback, revealing more of the ETA 2824-2 self-winding movement that provides 38 hours power reserve. The stainless steel case is 40 mm in diameter, and it looks fairly slim, possibly around 11 mm. It has a water resistance of 5 bar. Reference H32565135, price €775. Read more on the Hamilton website.

Edox Lapassion Open Heart – €1,295

The Lapassion by Edox is a women’s open-heart watch in stainless steel with details in pink gold PVD, with a swirling heart motif at 6 o’clock revealing part of the movement, though all you can see is the balance wheel jewel and bridge. The calibre is the self-winding Sellita SW200 running at 4 Hertz, power reserve 42 hours. The watch is 33 mm in diameter, 10.1 mm thick, and has an elegant crown with a polished cabochon on the left. Reference 85025-357RC-AIR, price €1,295.

Frederique Constant Ladies Automatic Heart Beat – €1,620

Pure romanticism from Frederique Constant with their Heart Beat, a 36mm watch made specifically for women with a double heart motif at 12 o’clock providing a glimpse of the balance. It has a self-winding FC-310 self-winding movement, visible through the display caseback and featuring a sort of decoration named Colimaçon. It runs at 4 Hertz and has a power reserve of 38 hours. It is probably the ETA 2824-2 or Sellita SW200. The watch can be personalized and preordered on the Frederique Constant website, price from about €1,620.

Raymond Weil Freelancer Open Aperture Watch – €1,670

The Freelancer Open Aperture by Raymond Weil has an open-heart aperture recalling tourbillon movements, and it has been specially designed to provide a good view of the balance. They achieved this by working closely with movement manufacturer Sellita and in fact the company call their calibre RW1212 and have announced it as their first in-house movement. It runs at the standard 4 Hertz and provides a 38-hour power reserve. The watch itself is an elegant piece, 42.5 mm in diameter and 10.6 mm thick, with rose gold PVD finish in this version – a range of other finishes is available. The 10 bar, 100-metre water resistance is a useful additional feature. Reference 2780-SC5-20001, price approximately €1,670. Read more on the Raymond Weil website.

Rado True Open Heart – €2,070

The True Open Heart by Rado is on the way to becoming a skeletonized watch, with quite a lot of the dial removed to show parts of the movement. You can see the balance assembly at 12 o’clock and the mainspring at 5 o’clock. The 40-mm case is in high-tech ceramic in a dark metallic colour, water resistance 5 bar, with a display caseback. Reference 01.734.0100.3.016, price €2,070. More information on the Rado website.

Zenith Chronomaster El Primero Open – €6,800

This version of the El Primero chronograph has all the things that I love and hate about these Zenith watches. The COSC chronometer-certified self-winding El Primero 4061 movement is a masterpiece, one of the few that runs at 36,000 vibrations per hour, 5 Hertz, providing tenth-of-second precision. The chronograph functions are controlled by a column wheel with a horizontal clutch. The opening on the dial reveals not only the balance but also the silicon escape wheel and lever, and a three-pronged continuous seconds hand. The watch is 42 mm in diameter, 14 mm thick, with sapphire crystal watchglass and caseback. The negative things are matters of taste: the chronograph minutes scale that is partly illegible, and the seconds scale in which the tenth of second subdivisions are interrupted by the hour indicators. All that amazing machinery and COSC precision, and then you can’t actually use it for getting accurate readings of elapse times. It’s pure theatre. Price €6,800, reference 03.2040.4061/69.C496. Further information from the Zenith website.