How do you read time read in the dark when there are no luminescent material applied to the markers on the dial and the hands of your watch? Well you turn the lights on, either the electrical light in the room or a torchlight. For the innovative good folks at HYT, they resorted to two miniaturised LED (light-emitting diodes) built into the watch that can light up the dial in darkness for around 5 seconds, allowing you to read the time, which by the way, is around 9.16 as seen above. Photos: © TANG Portfolio. Elfa / Timmy. 2015.

For those familiar with HYT, their H4 Metropolis, launched in late 2015, bears a striking resemblance to its older H1 sibling but there is one striking difference – there is an additional push-piece located between 4 and 5 o’clock.

What extra function could this be for, especially when the indications, the hour, minutes, seconds and power reserve display, are similar to what the H1 offers?

Well, under what the brand terms the “rider” at 6 o’clock (where the Arabic numeral “6” is) are two LEDs (light-emitting diodes). Upon activation, the entire dial is flooded with blue light.

Batteries are not used to light up the LEDs as the process is totally mechanical. The generator is located at between 4 and 5 o’clock. The mechanism is like a dynamo, whereby mechanical power is converted into light energy.

How are the LEDs activated on the HYT H4 Metropolis?

First, the push-piece at between 4 and 5 o’clock has to be rotated to wind the generator. After which, pressure on the push-piece will activate the two LEDs.

The illumination lasts for around five seconds, allowing one to read the time. After which, the process must be repeated to light the dial once more.

HYT’s H4 Metropolis is the first watch of the brand that lights up. It is also possible the watch industry’s first mechanical wristwatch featuring a light source that can mechanically illuminate the dial. The H4 Metropolis is housed in a 51mm diameter titanium case and is limited to 100 pieces. Photo: © TANG Portfolio. Elfa / Timmy. 2015.

With this innovation first employed in this 2015 H4 Metropolis, HYT is laying its claim as possibly the watch industry’s first mechanical wristwatch to be equipped with a light source that can mechanically illuminate the dial for time to be read.

HYT H4 Metropolis
Introduced in 2015
Technical Specifications:
• Exclusive mechanical HYT Calibre, skeleton manual-winding movement
• 28,800 vibrations per hour (4Hz)
• 35 jewels
• 65 hour power reserve
• Hand-bevelled and micro-blasted bridges, rhodium-plated bellows
• Retrograde fluidic hours, minutes and seconds
• Unstructured, fluid hour display
• Sapphire minute, seconds and power reserve dial, white minute indexes and numerals, black hour dial with white numerals, luminescent grey minute hand and numerals
• Regulator at 12 o’clock
• Small seconds wheel at 9.30
• Power reserve display at 2.30
• Blue light mechanical module with rewinding and push-button system with a crown at 4.30
• Rubber-clad screw-down black DLC titanium crown at 2.30 and 4.30
• Black DLC titanium dome at 6 o’clock
• Convex sapphire crystal with anti-reflective coating on the dial side
• 51mm diameter case in titanium and titanium black DLC bezel with brushed, shot-peened and satin-finished surfaces, 17.9mm thick
• Water-resistant to 50m
• Screw-down sapphire back
• Black rubber base strap with integrated Nomex canvas and black DLC titanium folding buckle
Limited to 100 pieces
Note:
The dynamo for the blue light mechanical module works when the crown at 4.30 is compressed. As soon as the button loosens, the light stops working until the full decompression of the additional barrel spring