I was there when G-SHOCK took Roni Size 1,375 feet beneath a Welsh mountain for the world's deepest underground rave

Watch launches don't usually involve abseiling into abandoned mines, navigating flooded tunnels or ziplining across underground ravines.

Then again, G-SHOCK isn't exactly known for doing things by halves.

Last week, the Japanese watchmaker celebrated the launch of its new GDG-B100 MUDMAN by organising what could become the world's deepest underground rave, featuring legendary drum and bass DJ Roni Size.

The event took place on 15 October at Cwmorthin slate mine in Eryri, North Wales, with a small group of ballot winners descending 1,375 feet (419 metres) beneath the mountain to reach the makeshift dancefloor.

I was among those who attended, and while I've experienced some unusual product launches over the years, this was certainly one of the most memorable.

Getting to the venue required a two-hour journey through dark, waterlogged passages, involving scrambles, abseils and zip lines, all under the supervision of qualified mine guides from adventure operator Go Below.

At the bottom, the reward was a one-off performance by Roni Size, supported by G-SHOCK Radio's DJ Nav, inside a vast underground chamber known as Deep Sleep.

The mountain became part of the music

What made the event particularly interesting was how the organisers incorporated the surrounding environment into the performance.

Engineers used vibration transducers to send elements of the music directly into the slate, while specialist microphones captured the resulting vibrations.

Speaking to T3 during the event, one of the audio technicians explained that the team had visited the mine several weeks earlier to experiment with the acoustic properties of the rock.

They tapped different sections of slate with a hammer to identify areas that produced interesting resonances, discovering that certain frequencies travelled through the material more effectively than others.

The engineers also took inspiration from traditional recording studios, where dedicated echo chambers were once used to add natural reverberation to music.

Using a separate underground chamber, they positioned a speaker and two ambient microphones to capture the mine's natural acoustics, which could then be mixed into Roni Size's performance.

The result was a DJ set that didn't simply take place inside a mountain, but incorporated the surrounding geology into the music itself.

Before Roni Size took to the decks, the Welsh national anthem, Hen Wlad Fy Nhadau, echoed through the underground chamber, paying tribute to the area's rich mining heritage.

A watch built for the underground

Of course, there was a reason G-SHOCK went to such extraordinary lengths to organise the event.

The new GDG-B100 MUDMAN is designed to withstand particularly demanding environments, making an abandoned slate mine a rather appropriate setting for its debut.

The rugged digital watch features shock, dust and mud resistance, alongside 200 metres of water resistance.

One of its biggest upgrades is the high-contrast Memory-in-Pixel (MIP) display, which offers improved readability over traditional LCD screens.

There's also a red LED backlight designed to help preserve night vision, Bluetooth smartphone connectivity and activity-tracking features, including distance, speed and pace measurements.

The new MUDMAN comes in three colourways: black (GDG-B100-1), dark green with orange accents (GDG-B100-1A3) and sand with a black bezel (GDG-B100-1A5).

As for the rave, G-SHOCK has submitted evidence for independent verification of its world-record attempt. Until that process is complete, its claim to the world's deepest underground rave remains unofficial.

Still, as far as unconventional product launches go, this one will be difficult to top.

The G-SHOCK GDG-B100 will be available soon at Casio UK for £200.

The full performance is available through G-SHOCK Radio on Mixcloud.

You can read more about Go Below here.