The Inversion Principle Tourbillon is a three minute central tourbillon with jumping hours and retrograde minutes, developed by Jaeger-LeCoultre alumnus David Candaux. Part of the proceeds from the sale of each watch will go to Fonderie 47, a charity dedicated to reducing the number of assault rifles in Africa. 

The watch was designed by Adrian Glessing of Virtualideas while the movement was conceived by constructor David Candaux of Du Val Des Bois. Candaux was formerly with JLC, where the projects he worked on included the Master Minuter Repeater and Spherotourbillon.  Making one revolution every three minutes, the Inversion Principle tourbillon cage has three seconds hands, two of which are always hidden under the gun-sight frame on the sapphire crystal. The visible seconds hand travels on a scale from one to 60 on the top third of the dial.

On the lower portion of the dial is the retrograde minutes, which travels through 240° before jumping back to zero. And at 12 o’clock is the jumping hour, which can be advanced in one hour increments by the pusher in the crown (and the crown can also be used to set the time conventionally).

There are twin power reserve displays for the six day power reserve – one on the side of the case, and the other on the top of the movement visible through the display back.

On the back is a plate covering the ratchet wheel, made from steel of a destroyed AK-47. This watch will help fund the destruction of 1000 AK-47 rifles.

20 will be made, with 10 each in white and rose gold. The case diameter is 42 mm, with a thickness of 14.6 mm. The retail price is US$350,000. – SJX

Founded by Belgian designer Benoît Mintiens, Ressence is all about simplified yet novel time display. The new Ressence Type 3 has a satellite disc time display that is now the trademark of the brand. Each of the discs, which indicate the hours, minutes, seconds, date and day, continuously rotate around the dial. And combined with the satellite disc time display are several other ingenious features.

But the convex dial appears to be completely flat against the domed sapphire crystal, thanks to the naptha-type fluid in the space between the dial and crystal. This minimises the refraction of light by the crystal, and thus increases legibility of the dial.

The dial and time display module – which itself comprises 28 gears and 57 jewels – are sealed in the liquid-filled sapphire bubble, with a thermal valve to compensate for temperature changes leading to expansion or contraction of the fluid.

In the photo above: the date is indicated on the outermost ring, and on the inside is the minutes with the minute hand at two o’clock. At eight o’clock sits the hours satellite, at noon the seconds hand, and at four o’clock is the day display.

This bubble is physically separate from the movement, as it must be due to the liquid, so the time display mechanism is driven by magnets linked to the movement. And naturally the base movement, an ETA 2824, is contained inside a soft iron cage to ensure the escapement is not affected by the magnets of the time display.

In addition, the Type 3 has no crown. Instead, the case back has different quadrants to wind or set the watch. The watch is wound by turning the case back. To set the date or time, the case back has to be turned to the appropriate quadrant.

And a gravitational setting keyless works means the time setting mechanism is disconnected once the watch is turned back to the dial up position.

This has a 44 mm titanium case and is a limited edition of 50 pieces. The price is €23,000, or about US$29,500.