Nivada Grenchen Opens the F77: Three New Titanium Open-Heart Watches

Black Tressed, Green Aventurine and Meteorite dials reveal the Swiss movement inside the most visibly mechanical F77 MKII yet.

The F77 is not short of dial variation. Since returning to the Nivada Grenchen collection, its distinctive 1970s case has appeared with woven textures, natural stone, meteorite and several different colours.

The latest release changes something more fundamental, as for the first time, the F77 becomes an open-heart watch, revealing the movement through an opening at six o’clock. The familiar steel construction has also been replaced by Grade 5 titanium, creating three watches that look and feel very different from the wider F77 MKII collection.

The F77 opens up

Open-heart watches are normally designed around the movement aperture from the beginning. But the F77 already had a strong and highly structured dial, so cutting into it could easily have disrupted the design. Nivada Grenchen has handled that by placing the opening at six o’clock, directly within the vertical axis created by the logo, hands and hour markers.

Rather than using a conventional circular cut-out, the aperture has an irregular, fractured shape. It reveals the balance wheel and surrounding components without turning the entire dial into a skeleton watch. Most of the dial remains intact, allowing each material to retain its own colour and texture, and the movement becomes another layer of the design rather than taking over completely.

The hour and minute hands retain their openworked construction, while applied titanium-coloured markers and white Super-LumiNova dots preserve the recognisable F77 layout.

Three very different dials

The three versions share the same case and movement, but the treatment of the dial changes the character of each watch considerably.

Black Tressed

The Black Tressed model is the most restrained of the three.

Its embossed carbon-style pattern develops the familiar woven texture associated with the F77, with a sun-brushed finish adding further variation as the dial moves beneath the light.

The dark surface also creates the clearest contrast with the exposed balance wheel at six o’clock. From a distance, it remains recognisably an F77. Look closer and the opening introduces movement, colour and considerably more mechanical detail.

This is likely to be the most versatile version, particularly for someone who likes the original textured F77 but wants something less conventional.

Green Aventurine

The Green Aventurine model takes the opposite approach.

Its dial is made from natural green aventurine, producing an irregular surface filled with small reflective inclusions. As with any natural material, variations in colour, texture and distribution mean that no two dials should appear exactly alike.

Nivada Grenchen has also placed luminous material beneath parts of the dial. In low light, the glow can diffuse through the fractured openings around the movement, extending the open-heart idea beyond the balance wheel itself.

The result is the most expressive watch of the three. The stone provides depth in daylight, while the concealed luminous treatment changes how the dial appears after dark.

Meteorite

The Meteorite edition combines two materials that feel particularly appropriate together.

Grade 5 titanium is widely associated with aerospace engineering, while the dial is cut from genuine meteorite. Its natural crystalline structure creates the irregular geometric patterns seen across the surface.

These patterns are formed within the material itself rather than printed or engraved onto it. Every section is therefore different, making each finished dial unique.

The open-heart aperture adds another kind of structure beneath it: the organised, repeated motion of a mechanical balance wheel set against a surface formed beyond Earth.

That could have become overly theatrical. In practice, the monochrome palette keeps the watch relatively restrained.

The F77 moves into Grade 5 titanium

All three watches use a 38mm Grade 5 titanium case, measuring 46.2mm from lug to lug.

Titanium provides a noticeable reduction in weight compared with stainless steel, but Nivada Grenchen has not treated it purely as a technical material. Vertical brushing covers the broader surfaces, while polished details define the edges and geometry of the case.

The octagonal bezel and its eight visible screws remain, preserving the architecture that has defined the F77 since its original appearance in 1977.

A double-domed sapphire crystal protects the dial, while the screw-down crown and 100 metres of water resistance keep the watch suitable for everyday use.

Drilled lugs make strap changes easier, and each version is available on either a vertically brushed Grade 5 titanium bracelet or a canvas Velcro strap.

The caseback can be specified in closed titanium or with a flat sapphire display window. The latter creates a useful connection between the two sides of the watch: the balance is visible through the dial, while the bridges, gears and winding rotor can be viewed from behind.

A new movement for the F77

Inside is the Swiss-made Soprod M100BV automatic movement.

The calibre is derived from Soprod’s established A10 architecture, with the “BV” designation referring to the visible balance wheel. It runs at 28,800 vibrations per hour, or 4Hz, uses 25 jewels and provides approximately 42 hours of power reserve.

The movement displays central hours, minutes and sweeping seconds, with no date window to interrupt the three dial designs.

A 42-hour reserve is conventional rather than exceptional, particularly alongside the longer-running movements now appearing elsewhere in the F77 family. That is not really the point of this version, however.

The M100BV has been selected because its architecture allows the mechanical regulating organ to become part of the watch’s appearance. The movement is not simply powering the design from behind it; it is visible within it.

Familiar architecture, different priorities

The F77 MKII Titanium Open Heart does not replace the conventional F77.

The steel Tressed models remain the cleaner and more historically direct interpretation. The closed natural-stone editions allow their materials to occupy the entire dial. The 100 Years collection adds longer power reserves and extremely limited production.

These new watches offer something else.

They combine the lightness of titanium with the individuality of aventurine or meteorite, then introduce visible mechanics without abandoning the shape and proportions that made the modern F77 successful.

Of the three, the Black Tressed is the easiest to wear. Green Aventurine makes the strongest visual impression. Meteorite sits between them, adding a genuinely unusual material while retaining a largely monochrome appearance.

Same case. Same movement. Three substantially different results.

Nivada Grenchen F77 MKII Titanium Open Heart specifications

• 38mm diameter
• 46.2mm lug-to-lug
• Grade 5 titanium case
• Brushed and polished finishing
• Double-domed sapphire crystal with anti-reflective coating
• Screw-down crown
• Drilled lugs
• 100 metres of water resistance
• Black Tressed, natural Green Aventurine or genuine Meteorite dial
• Open balance wheel at six o’clock
• Titanium-coloured hands and applied markers
• White Super-LumiNova
• Swiss-made Soprod M100BV automatic movement
• 28,800 vibrations per hour
• 25 jewels
• 42-hour power reserve
• Closed titanium or sapphire exhibition caseback
• Grade 5 titanium bracelet or canvas Velcro strap
• Swiss Made

The three Nivada Grenchen F77 MKII Titanium Open Heart models launch on Thursday 22 October 2026.