Easily one of the most beloved watch complications in the world is the melodious minute repeater. Minute Repeater watches chime the time out loud, on demand, usually by the push of a button, slide, or lever on the side of the watch. An elaborate labyrinth of mechanics, minute repeaters chime beautifully pitched sounds to signal the hour (a low-pitched note); the quarter-hour (a double note with both a high and a low pitch); and the minutes past the most recent quarter-hour (a high-pitched tone).

One of the most difficult complications to build, minute repeater watches usually house more than 300 tiny parts in their movements, including gongs and hammers to chime the time. The work that goes into building a minute repeater renders it one of the most expensive watches on the market and one of the rarer breeds. They are typically made in limited numbers and only by top haute horology brands.

While building the mechanics for a minute repeater is challenging, many watch brands agree that the more difficult feat is achieving the perfect sound (created when the hammers hit the differently tuned gongs) in terms of pitch, loudness, length and more. The number and shape of hammers used, the case and gong materials used and several other factors influence the final sound.

How Minute Repeaters Work
Minute Repeater watches house timekeeping parts, as well as the striking mechanism for the repeater, which is activated by the wearer. Additionally, there is a complex system that enables the striking mechanism to track the time to then chime the right amount of times.

Essentially, in a minute repeater, the timekeeping function operates separately from the chiming function. The repeater (which sounds when the tiny metal hammers strike the gongs) is armed via a tensioning spring or system. The wearer pushes the slide to create tension within the chiming spring. Then, as the slide is released, the hammers spring into motion, striking the gongs (thin strips of metal typically located on the perimeter of the case) to sound the time. To track (and ultimately chime) the exact time, the chiming portion of the movement uses tiny gears that work with the timekeeping portion of the watch to constantly keep in sync. They relay the exact time information to a series of racks, levers, and cams that, in turn, activate the hammers. It is all a highly orchestrated arrangement of mechanics. Generally, it takes a single watchmaker 200 to 300 hours to assemble the minute repeater movement.

The sound is achieved when each hammer hits one of the gongs and the reverberation projects the sound outwards. Most minute repeaters have two hammers and two gongs. The gongs are usually of different thicknesses or width to achieve distinct sounds. Generally, one hammer hits one gong for the hour. An opposite hammer hits the second gong to sound the minutes after the quarter-hours. For the quarter-hours, the two hammers alternate hitting the two gongs to achieve the high/low double sound that signals the quarter-hours. It should be noted that some repeater watches can have as many as five hammers and multiple gongs to create different sounds.

History and Future of Minute Repeaters
Chiming watches have their roots in the early clock towers of the 14th and 15th century that would strike on the hour, day and night. The invention of the chiming clock is widely credited to Daniel Quare, an English watchmaker who invented the quarter repeater at the end of the 17th century. Later, Thomas Tompion added a second hammer to the chiming clock to achieve differences in tones. By the 18th century, chiming clocks could be found in the homes of royalty and the wealthy and, thanks to their clear sounds, allowed them to know the time in the dark without having to light an oil lamp or candle.

In 1783, Abraham-Louis Breguet invented the gong spring and two steel blades instead of bells to do the chiming. This also allowed for further miniaturization to convert the chiming clock into a portable pocket watch. In the 19th century, the advent of electricity rendered the minute repeater was virtually useless. However the beloved sound and beauty of the minute repeater made it an enduring and coveted complication.

Today’s minute repeaters have become works of art and technical prowess. Some top watch brands work side-by-side with musical and engineering institutes to develop the perfect sound for their watches. Others still do it the old-fashioned way: by simply listening to and approving or disapproving the sound. Brands are also working to develop more advanced repeaters that chime different measures of time. Some brands pair their repeaters with other key watch complications, including automatons, perpetual calendars and tourbillon to create Grand Complications.

Because of the incredible mechanics housed inside, the minute repeater watch and its variants (including 5-minute repeaters, 10-minute repeaters and sonneries) are incredibly expensive. As such, it is a great category to keep an eye on in the vintage and second-hand market.

Grand Complications the watch masterpieces in the world of haute horology, a testament to the unparalleled skill of a master watchmaker. We explain what makes a watch a Grand Complication and take a look at three of history’s most important and complicated watches.

What is a Grand Complication?
Before we can delve into the world of grand complications, we should quickly review what exactly is a watch complication. The most basic definition for a complication is: any mechanical watch function beyond simply telling the time. Watch complications include alarms, chronographs (or a stopwatch) and day or date displays.

While we may quickly dismiss these complications as commonplace on modern watches, they were significant breakthroughs in watchmaking when first introduced. These core complications are proof positive to the watchmaker’s skill, craftsmanship and ingenuity to layer in additional mechanical functions in such a small watch case.

Grand Complications, in turn, are considered the most complex and highest achievement of haute horology. While watchmakers, executives and collectors debate over what really qualifies a grand complication, the generally accepted definition of a Grand Complication is a portable timepiece that includes a minute repeater, moon phases, perpetual calendar, split-seconds chronograph and a grand and petite sonnerie which is a quiet gong that strikes every quarter of an hour.

The High-Stakes World of Grand Complications
Grand Complications are a badge of honor for watchmakers and brands, the finest of fine watchmaking. These premier timepieces can take more than 10 years to develop. They also test the skill of a horology master who needs to expertly layer together all these different components– and to make each function work flawlessly. Grand Complication watches can include upwards of 1,300 individual parts that need to neatly fit inside an incredibly limited space.

The art of Grand Complications effectively is a game of one-ups-manship as brands compete to hold the title of the World’s Most Complicated Watch. And as brands introduce ever more complex and elaborate Grand Complications, they raise the bar on what a Grand Complication is—hence the disputed definition of a Grand Complication.

3 Historical Grand Complications
3. The Most Expensive Grand Complication Sold at Auction: The Henry Graves Jr. Patek Philippe Supercomplication One of the most storied and renowned watches by Patek Philippe is the Henry Graves Jr. Supercomplication. This pocket watch was commissioned by the wealthy banker Henry Graves Jr. in 1925. It required seven years to design and build the watch’s 24 complications which include a moon phase, a perpetual calendar and sunrise and sunset indicators. Most notably, the Henry Graves Jr. Supercomplication includes a celestial map of the sky above New York City, as seen from Graves’s posh 5th Avenue apartment.

Although its title for the world’s most complicated was usurped by another Patek Philippe design in 1989, it remains the most complicated watch designed without the aid of computers. It was most recently sold at a Sotheby’s auction in 2014 for a record-breaking $24 million USD.

2. World’s Most Complicated Pocket Watch: Vacheron Constantin 57260The current title for the Most Complicated Watch in the World goes to the Vacheron Constantin 57260. The watch debuted in 2015. It took Vacheron Constantin watchmakers eight years to develop. This hefty two-pound watch includes 57 complications made up of 2,826 individual components. (For comparison, the former title holder was the Patek Philippe Calibre 89 which boasted 33 complications in 1989.) It was built entirely by hand by three watchmakers.

This Vacheron Constantin Grand Complication was sold to a private collector for an undisclosed sum but experts estimate it had a $10 million USD price tag.

1. Oldest Known Patek Philippe Grand Complication: Stephen S. Palmer Patek Philippe Grand Complication No. 97912 This recently discovered Grand Complication by Patek Philippe was first manufactured in 1898 and predates what was previously considered the first Patek Philippe Grand Complication by 12 years. However, because this Grand Complication was a part of a private collection, it only became known to the public in 2013 when it made its debut on the Christie’s auction block. The Palmer Patek Philippe Grand Complication sold for $2.25 million USD.

This pocket watch includes the core Grand Complication criteria: moon phases, a split-seconds chronograph, minute repeating perpetual calendar, and a grand and petit sonnerie. It is also made of a beautiful and unconventional 18K pink gold.

It was originally purchased in 1900 by Stephen S. Palmer, the president of the New Jersey Zinc Company and an avid watch collector. Palmer traveled to Patek Phillipe’s historic headquarters in Geneva to finalize the purchase of the Grand Complication. It is believed the Grand Complication rarely left the security of a bank vault as it was auctioned in near-perfect condition.