The times had changed. Life was no longer sedate; it was becoming fast-paced, packed with action. And perhaps, just perhaps, the watch world wanted to reflect this spirit. Enter the jumping hour. One of the first kinds of digital display, it did away with the slow progression of the hour hand on the dial face. Instead, it introduced a window to display the hour of day. And since the numeral would change suddenly on the hour, this complication was given the name, 'jumping hour'.

The jumping hour makes use of a rotating disc bearing numbers for the hours. The rotational movement of the disc helps mark the time, with the hour appearing in an arc-shaped window. In some watches, the movement is slow and continuous and the window is fitted with guidelines for a clear indication of the time of day. The other option, as adopted by watchmakers at Audemars Piguet, is more complex. "Here, the disc advances in hourly increments, driven by an intermediate mechanism, while a wheel continuously cocks a lever that acts on the hour disc. At the turn of the hour, the accumulated energy causes the disc to jump instantly to the next hour position via the lever, which now begins its next cocking cycle." (Source: As Time Goes By, Audemars Piguet) This ensures that the jump is precise, and the switch barely perceptible to the observer.

One of the early developments in jumping hour watches can be traced to Breguet, the master watchmakers, who received a patent in 1926 for their watch without hands. It featured a rotating dial featuring jumping hours displayed in an aperture. Patek Philippe, meanwhile, began the manufacture of wristwatches with jumping hours and minutes in 1929. These watches, in gold or platinum, flaunted rectangular or tortue-shaped cases. The first digital Rolex was the so-called 'Jump Hour' Prince where only the hour was shown digitally. In the series made in the early 1930s, there was no dial, just two overlapping ivory coloured discs, the hour disc having more stylised numerals. The top of the case has a small wedge-shaped aperture for the hours and a larger sector for the minutes.

In 1986, Franck Muller, after painstaking research, came up with a tourbillon wristwatch with jumping hours that change precisely at the 60th minute. And that's not all. He was responsible for the double jumping hour watch in 1994 for which he also received a patent. This one lets the wearer adjust the hour of a second time zone independently from the local time. Then Corum designed the Classical Heure Sautante (Jumping Hour), which won the 'Watch of the Year 2002' at the annual competition organised by Montres Passion and Uhrenwelt magazines.

On the dial of this watch, a single hand turns to show the passing minutes. The full hours appear through a trapeze-shaped aperture at 12 o'clock and are never out of sight. The instantaneous jump from one hour to the next is the true attraction of this model. For some reason, wristwatches with jumping hours have never been made in large quantities. Patek Philippe stopped their production on the grounds that they were not very popular. Rolex, which attempted mass production with the Prince watches, too could not effect a change. Which explains why jumping hour watches are such a rarity today. Here's looking at some jumping hour watches.

	Girard-Perregaux In keeping with the spirit of innovation, Constant Girard developed a split-seconds chronograph with jumping seconds in a pocket watch in 1880. The seconds were divided into quarters and the hand, making a full turn of the dial in one second, imperceptibly marked the quarter seconds. Over a century later, the jumping seconds function has been incorporated in an elegant wristwatch called the Vintage 1945 XXL.
	Rainer Nienaber The watch shown here is designed by Rainer Nienaber and claims to be different from other jump hour watches in two ways: the first is the size of the hour indicator, which is the largest ever developed in this complication. The second is the element of precision; the jump hour functions with a precision of 10 seconds to the top of the hour. "This," it is said, "differs from the current standard of 45-60 seconds used in other jump watches and involves a substantial modification to the base movement".
	Vacheron Constantin From the Les Complications collection comes this self-winding wristwatch with jumping hours. The hours are shown in a dial window and the minutes by an onyx pointer rotating opposite the minute track. The watch has a silvered dial and yellow gold case with transparent sapphire caseback.
	Corum The Classical Dragon Heure Sautante is a hand-painted creation, which uses the ancient art of Russian miniature painting. Only 50 specimens of this limited edition have been created and each dial is unique in the colours that are used on the dial.
	Fossil For a varied interpretation of the jumping hour, check out Fossil's Big Tic. The watch exhibits the seconds in blinking mode on the dial in the background. It's a system that's been patented by Fossil Inc, USA.
	Audemars Piguet This watch, from the Audemars Piguet Museum, has jumping hours and features a digital display of the minutes. Made in 1929, the watch has a case in 18-carat white gold.
	Piaget This model, called the Emperador 8 Jours, is one of Piaget's limited edition watches. It has a silver dial with gold indexes and is fitted with a leather strap and ardillon buckle.
	Dubey & Schaldenbrand Dubey & Schaldenbrand created the Aerodyn Jump Hour in a limited series of 100 pieces in 18-carat rose gold and 300 pieces in 316 L stainless steel. The watch, flaunting a bold, tonneau-shaped, curved, streamlined Aerodyn case, has a large V-shaped jumping hour window at 12 o'clock and an off-centre second hand sub-dial. The watch is fitted with a vintage 1960s mechanical, hand-wound movement.
	Cartier This one's a Tank model with jump hours and rotating minutes dating back to 1928, which was purchased by the Maharajah of Patiala. The case is satin-finished gold and the winding crown is at the top between the strap attachments.
	Bell & Ross Designed in collaboration with Vincent Calabrese, the Vintage 123 Jumping Hour associates a complex movement with an innovative dial reading system. The watch is in 950 platinum, has an ivory dial and is fitted with an alligator strap.