Men who visited Vacheron Constantin's booth at this year's Salon International de la Haute Horlogerie (SIHH) were disappointed. In a bold strategic move, the luxury Swiss watchmaker decided to launch women's novelties this year - and women's only.

"We wanted to make a strong statement," says Christian Selmoni, the brand's artistic director. "Women's watchmaking has changed a lot in the past few years. We have moved from a market where it was just men buying watches for ladies. In most of the cases, those weren't [done in the] best way to create watches."

Vacheron Constantin wasn't the only one at SIHH hoping to tap into the women's demand for mechanical watches. Brands such as Audemars Piguet, Baume & Mercier and Jaeger-LeCoultre are also jumping on the bandwagon to change the notion that women's watches are more about carats than calibre.

"Women today are not necessarily only looking for watches with diamonds, but more and more active [designs]," says Octavio Garcia, Audemars Piguet's chief artistic officer.

Montblanc International, for example, issued its first couples watch, Seconde Authentique Pour Elle & Lui, this year, featuring its own manufactured automatic movements. Lutz Bethge, the brand's CEO, says that while there are those who still prefer the convenience of quartz timepieces, there is an increasing interest in small complications.

For brands with a long history in watchmaking, crafting women's mechanical models is no new endeavour, as the first wristwatches were worn mostly by women who found pocket watches impractical. Jaeger-LeCoultre's first mechanical wristwatch, for example, was actually made for women.

Nevertheless, the 1980s fad for quartz models diluted the popularity of women's mechanical watches, and it wasn't until this year that the industry finally saw a comeback in automatic watches for women.

The emerging trend may also have something to do with the buying power in China. "Ten years ago, the men's market was really strong in China but, recently, we have seen that the women's market has improved substantially," says Jaeger-LeCoultre's CEO Jerome Lambert. "In China, quartz watches are completely out of fashion and I think it is changing the game for the rest of the world."

Baume & Mercier's CEO Alain Zimmermann agrees that the trend stemmed from a market change in Asia and says the brand placed more emphasis on the automatic side of women's collection this year.

There is, however, a significant challenge in making smaller novelties, in that the watchmaker must achieve the perfect balance between size and performance, and this difficulty is even more pronounced for women's watches.

"Women's watches couldn't have complications in the past because they were too tiny to fit in anything but a quartz battery," Selmoni explains.

Giulio Papi, veteran watchmaker and co-founder of Audemars Piguet Renaud & Papi (APRP), agrees. He says that to make a calibre fit in a smaller case, the watchmaker would have to sacrifice either power reserve or precision. One possible solution would be to source or develop new material for the balance spring, allowing it to work more efficiently.

Technological breakthroughs in compact, high-performance calibres have influenced a growing interest in women's mechanical watches.

In October 2010, Omega revived its Ladymatic model driven by the Calibre 8520 - the smallest automatic movement the house had ever made and one of its first self-winding watches designed specifically for women. The chronometer's 34mm diameter case houses Omega's exclusive Co-Axial movement and is equipped with the Si 14 silicon balance spring, making it more resistant to external shocks and environmental disturbances, hence higher accuracy. The watch also has a 50-hour power reserve. Last year, Omega fitted the Co-Axial movement technology into the even smaller 27mm diameter case, adding to its Constellation family.

These technical innovations have been observed across the board, as fine watchmakers set their eyes on smaller and thinner cases to ensure comfort to wear and a feminine style for women's novelties, while maintaining functional properties, such as power reserve and precision. Vacheron Constantin's latest manual-winding Patrimony Traditionnelle Lady, for example, has a 33mm-diameter case and 40-hour power reserve, while Jaeger-LeCoultre's Grande Reverso Lady Ultra Thin Duetto Duo has an impressive 8.87mm thin case fitted with two dials. Its Calibre 864A is equipped with a balance oscillating at a frequency of 21,600 vibrations per hour.

For newcomers, such as Montblanc, within its 34mm-diameter red gold case, its Star Classique Lady Automatic houses an automatic movement calibre.

Brands such as Audemars Piguet and Piaget, have taken a different route, choosing to adapt their iconic men's watches for women.

"It's easier to make a bigger watch. Why not change the culture for ladies," Papi says. "The watch will be bigger but with good precision and also an elegant and feminine design."

Celebrating the 40th anniversary of its Royal Oak sports watch last year, Audemars Piguet adds two mechanical models with a 37mm diameter case to the family.

The limited-edition Royal Oak Offshore Ladycat Chronograph houses a mechanical self-winding movement with a 40-hour power reserve and is equipped with an 18ct gold oscillating weight.

For the first time, the brand is launching a self-winding version for the Royal Oak 37mm. Its feminine white gold case is paired with a blue alligator leather strap and a total of 2.46ct diamonds on its dial, bezel and clasp.

Piaget is also breaking new ground. The brand is updating its signature ultra-thin Altiplano, adding a skeleton version with a gem-setting not only on the decorative elements, but also the skeleton movement, the entire gold main plate and functional parts, featuring approximately six carats of diamonds. Its 18ct white gold case, 40mm in diameter, houses Piaget's innovative Calibre 1200D, only 3mm thick. With a 6.1mm thick case, the world's thinnest automatic diamond-set skeleton watch appeals to men and women alike. "I think 40mm is a good size for a classic piece," says Piaget's CEO Philippe Léopold-Metzger. "This is the perfect combination between Piaget the watchmaker and Piaget the jeweller."

For those who see this as an easy way out, however, the process of transforming the design for a men's watch to a women's wasn't as simple as it might look, says Garcia of Audemars Piguet. The brand recently changed the design for its 37mm Royal Oak model.

"With an iconic watch design like the Royal Oak, [even changing something that is] a hundredth of a millimetre is a challenge. The magic about this collection is when someone sees it and says nothing has really changed, that means we did our job," he says, adding that the difficulty lay in reproducing the design on a smaller dial, while keeping its balance.

"Getting all the little details together, getting them right and getting the translation of our design through [the] industrial process was the real challenge."

This sweeping change in the industry isn't simply affecting more technical watch brands. Even watchmakers that are famous for their high jewellery, such as Van Cleef & Arpels and Cartier, are adding mechanical movements to their portfolios.

Cartier's new Envol d'un Phoenix is a self-winding mechanical movement, while its Baguette Panthère watch is currently powered by a manual winding movement. Van Cleef & Arpels' Lady Arpels Ballerine Enchantée is now fitted with the brand's Poetic Complication - a double retrograde movement inspired by a pocket watch in 1927. At the push of a button, the automatic movement allows the wings of a half-ballerina-half-butterfly creature on the dial to rise gracefully to indicate the hours and the minutes scale.

Unlike traditional watchmakers who start the design with the calibre, the high jeweller has a different approach.

"We are very interested in storytelling," says Van Cleef & Arpels' international marketing and communications director Jean Bienayme. "We usually start with the story we want to tell and if the movement is part of the story, for instance the ballerina, we love to explore the movement."

The trend for women's mechanical watches has provided high jewellers with a chance to develop the movements and watchmakers to showcase their artistic crafts in gem-setting, enamelling and guillochage while keeping to their house style. Papi says it's a welcome challenge. "This way, I can better understand the brain of the ladies," he quips.