I don't mind saying that at the last couple of SIHH fairs Vacheron Constantin has been underwhelming. Its emphasis has been on metiers d'art and jewellery watches, which is all well and good, but Vacheron Constantin is a giant of hardcore horology, and on that front things have been quieter (bear in mind 2013's Patrimony ultra-thin minute repeater was launched at Watches & Wonders in Hong Kong).

Moreover, Vacheron's powers-that-be knew that we knew that they knew that everyone knew the brand's lack of a pure in-house chronograph movement was becoming more of a glaring omission with each passing year. In recent times Chopard, Cartier, Panerai, Girard-Perregaux and Glashutte Original are among those to have launched haute-de-gamme chronograph calibers. Where was Vacheron's? Something needed to be done.

Something has been – and how. At SIHH last week Vacheron Contstantin launched three different chronograph calibers that have been in development since as far back as 2008 – and which, quite frankly, knock each of the above contenders into a cocked hat. They are also joined by a new haute horlogerie dual time caliber, and an ungraded version of the Lemania-based 1141 chronograph Vacheron has relied upon up to now. It's all intended to mark the brand's 260th anniversary, and we are talking fireworks. Here are the five Harmony movements.

Vacheron Constantin
Vacheron Constantin

The watches housing these movements are all in a svelte, cushion-style case shape inspired by a 1920s model, making up a new line that the brand describes as a “sculptural collection intended to host innovative in-house developments.” Alrighty then. The collection goes by the (slightly toe-curling) name of Harmony – apparently a reference to the Vacheron Constantin's ties to classical music and ballet, but no matter.

The unquestionable star of the show – and of the whole SIHH – in both technical prowess and sheer, heart-stopping beauty, is the Ultra-Thin Grande Complication Chronograph. It's a pure thoroughbred stunner.

Vacheron Constantin
Vacheron Constantin

Want one? Tough luck – only 10 are being made, all in platinum, at a price of £262,000 a pop (all prices in this article are subject to change). But this really is one of the most advanced and sublime chronographs we’ve encountered, and one of the slimmest at 8.40mm in its case. It’s a monopusher in the classic style, with a split-seconds function activated by a separate pusher at 2 o’clock. The dial is gorgeous, with painted blue numerals, a red tachometric scale and leaf-style hands all inspired by the 1920s look. Besides the chronograph minutes and hours subdial, you’ve got a power reserve – 51 hours – at 6 o’clock.

But, as you might expect, the real fun starts when you turn the watch over.

Vacheron Constantin
Vacheron Constantin

The movement, calibre 3500, is 5.20mm thick – making it 0.05mm slimmer than the ultra-thin, cushion-shaped, split-second monopusher from a certain Genèvoise rival of Vacheron Constantin’s. Its power reserve is also three hours longer.

Patek Philippe’s watch, moreover, is hand-wound – the really unexpected thing about the Harmony Ultra-Thin is the fact that it’s an automatic. It has an amazing peripheral oscillating rotor that ensures you still get that classic view of the chronograph movement, in all its Poincon de Genéve-finished glory.

Vacheron Constantin
Vacheron Constantin

There’s a host of other refinements Vacheron Constantin has developed. Instead of the now-common vertical clutch, Vacheron has employed a lateral coupling clutch mechanism that includes a new “friction” system to eliminate the tiny jump chronograph seconds hands tend to make when activated. There’s also a blocking system for the rotor when the barrel is sufficiently wound, to avoid excessive tension in the mainspring. And so it goes on.

Next up is the Harmony Tourbillon Chronograph. A tourbillon chronograph is unusual enough, but a tourbillon monopusher is just ultra, ultra-rare.

Vacheron Constantin
Vacheron Constantin

Of particular interest here is the “dragging 45-minute counter”, instead of the traditional 30-minute register, as well as refinements to optimize durability of by protecting the chronograph from false-start activation (a common cause of damage to chronographs is when the pusher is not pressed firmly enough, causing gears to move but the mechanism not to activate).

This time we have a 65-hour power reserve, and a tourbillon carriage that acts as the running seconds and a slow, 2.5 Hz frequency. One the reverse, a huge gold bridge for the tourbillon features some seriously baroque hand-carved decoration.

Vacheron Constantin
Vacheron Constantin

Once again, finishing meets the highest Poincon de Genéve standards. The watch is also cased in 950 platinum, and 26 models will be produced, priced at £233,000 each.

While the Ultra-Thin and the Tourbillon are extraordinary watches, the Harmony Chronograph is perhaps the absolute purists’ choice: a hand-wound, monopusher chronograph in the classic style, with a retro-beautiful pulsometer dial and a movement you just want to dive into (sadly we didn’t manage to get our own good shot of the back of the watch, such were the trying light conditions in Vacheron’s SIHH booth). As with the tourbillon model, the watch features a "dragging" 45-minute chronograph register at 3 o'clock.

Vacheron Constantin
Vacheron Constantin
Vacheron Constantin
Vacheron Constantin

The movement contains the various innovations mentioned above. For horological tech junkies, here's another couple to add, found in all the watches: 1) a system for enhancing the precision of the chronograph operation, using two hammers for the start/stop/reset functions instead of one; and 2) a cone-shaped gear between the winding pinion and the crown wheel that enables very smooth, gentle winding. A spherical differential, also fitted with a cone-shaped gear, serves to indicate the power reserve and also adds longevity to the mechanism.

The Harmony Chronograph is being produced in a limited edition of 260 pieces, priced at £53,450.

Rounding out the Harmony collection are two further models. The Harmony Chronograph Small Model is a hand-wound chronograph featuring Calibre 1142, a Poincon de Genéve enhancement of the Lemania-based Calibre 1141 that features in the brand's hitherto flagship chrono, the Patrimony Traditionelle. With a gem-set rose-gold case, there are 260 pieces being made, priced at £50,550.

Vacheron Constantin
Vacheron Constantin

Lastly, we have the Harmony Dual Time, for which Vacheron Constantin has developed a new automatic movement, Calibre 246DT. It's a bit of a curio: instead of a 24-hour hand, you have a 12-hour subdial at 4 o'clock and a day/night subdial at 7 o'clock. The result is unusual and asymmetric, and I picked up both positive and critical responses to this in Geneva.

Vacheron Constantin
Vacheron Constantin

I found it interesting and rather attractive: an elevation of a common complication to something highly refined, luxurious and classical. The dial is gorgeous and finished to perfection, including the gold rims around the sunken subdials, and that magnificently decorated winding rotor exudes top-end quality. As you'd expect, Vacheron has refined the dual time mechanism too, with the innovation that all settings may be done by the crown in both directions, without any risk of damaging the mechanism.

The Harmony Dual Time is being produced in a run of 625 pieces, priced at £31,100 for the 40mm version. A bejewelled 37mm, the Dual Time Small Model, is being produced in a run of 500 pieces, priced at £35,950.

There's no question that the Harmony collection is a massive step forward for Vacheron Constantin, thanks to those three world-class mega-chronographs. It has now joined the likes of Patek Philippe, A Lange & Sohne, Breguet and Montblanc (thanks to its Villeret/Minerva facility), among very few others, in the ranks of true top-level chronograph manufactures. What will be interesting to see for the future is how both the Harmony collection develops as a dedicated area for new technical discoveries at Vacheron, and how its over-all chronograph offering evolves. For instance, what will be the future of the Patrimony Traditionelle chronograph featuring the Lemania 2310 base calibre? Could we see a Patrimony monopusher featuring Calibre 3300? And what of the Overseas chronograph featuring a Frederic Piguet (Blancpain)-derived automatic movement? The expectation must be that, now that it is fully in the chronographs game, here too we'll see something new in the not-too-distant future.