HYT does things its own way, and discards these received ideas. Need a known quantity to hang on to? Good news: the H4 Metropolis tells the time. As for the rest, you will need to forget anything that has been seen, designed, or even imagined before now.

Nothing has changed, except the essential

The chassis is a familiar beast. Since the start of the year, the H4 has had more ink in publicity than it has in its capillary. It is based on the same movement architecture as the H1, HYT's inaugural piece, which has been completely skeletonised.

With a 65-hour power reserve, it unveiled its sculptural mechanism for the very first time and opened up a new creative universe for HYT. One so appealing that the brand decided not to meddle with it: the new H4 Metropolis is virtually a carbon copy of its big brother. Or is it?

All is not as it seems

Using this as its basis, HYT has returned to its favourite game: creating, surprising, sometimes unsettling, always astounding. This time the brand has applied a radiant idea, as brilliant as it is difficult to spot at first glance.

Only eagle-eyed enthusiasts will have noticed an intriguing detail: the presence of two push-pieces. What could they be for, on a model with hours, minutes and seconds? The answer is a first for HYT – probably in watchmaking as a whole.

A fully illuminated project

The H4 Metropolis is a piece equipped with a light source. Under the rider at 6 o'clock, HYT has concealed two LEDs. Once activated, they flood the entire dial with blue light. At night, the green fluid is energised by this light source, becoming perfectly visible. At the same time, the wash of light flows into every nook and cranny of the calibre, literally bringing this skeleton architecture to life, and defying the laws of watchmaking.

The source of energy is purely mechanical. "Starting with a blank sheet is what we know. That's how all our models have been created", explains Vincent Perriard, CEO of HYT Watches. "But here, with the light complication, a new challenge was set: we had to start using our own existing calibre as a complete, functional basis. We basically had to add a piece to a puzzle which was already finished".

Lumens ex machina

The generator has been nestled between 4 and 5 o'clock. It is invisible, and activated by the push-piece located opposite on the case middle. The process is broadly that of a dynamo: converting mechanical power into light energy. It is the rotation of the push-piece at 4:30 that winds the generator. Pressure on this same push-piece then activates the two LEDs which bathe the Metropolis in a soft blue light.

This illumination is possible for a maximum of five seconds, after which the mechanism must be reinitialised. No battery is needed for this process, which is fully mechanical. Three factors made it so tricky to develop: the extreme miniaturisation, the curved shape, and the fact, once again, that no development of this type had ever been achieved before.

The H4 Metropolis will be released as a run of 100 pieces with a 51 mm titanium and DLC case, available from October 27 2015 previously at Colette in Paris and worldwide from mid-November.

"The coherence of the idea seduced us ", explains Vincent Perriard. "Before HYT, we were told that having a movement running with a liquid was simply impossible. Before the Metropolis, lighting up a dial was only possible with a battery. And, what is more, a liquid must never be used in conjunction with an electrical current. But, evidently, we’ve done all of those things. In reality, the only limits are those we set ourselves".