Logical Ones finely-finished, in-house calibre features Romain Gauthiers award-winning, 21st-century reinterpretation of a chain-and-fusee constant-force mechanism, plus pioneering winding pusher.

This invention contains a friction-minimising ruby-link chain and innovative snail cam to ensure constant timing precision over the entire 46-hour power reserve.

And in a world-first, the movement is wound via an ingenious, ergonomic pusher.


  • Logical One calibre, Romain Gauthier
  • Logical One calibre, Romain Gauthier

“When I designed Logical One, I worked from the premise
that for a ‘precision’ watch to be truly precise,
it should have constant energy.”
Logical One calibre, Romain Gauthier

Innovative snail cam

Romain Gauthiers patented constant-force mechanism contains an innovative cam in the shape of a snails shell, connected to the mainspring barrel via a ruby-link chain.

With the snail cam and mainspring barrel configured so they are on the same plane, force is transmitted in a straight line for an ultra-efficient transfer of energy.

Logical One calibre, Romain Gauthier

Chain featuring steel links with ruby rollers

The relatively short length of the chain allows it to contain strong, generously sized links in steel featuring rollers made from low-friction, hard-wearing synthetic rubies.

The patented chain is joined together and taken apart via a smart snap-clip system for ease of servicing.

Ergonomic winding pusher

Ergonomic winding pusher

Winding Logical One is a tactile pleasure thanks to the patented push button winding system, with the pusher set into the caseband at 9 oclock.

Another demonstration of Romains clever engineering, the pusher efficiently transmits force to the mainspring barrel on the same plane.

Mainspring barrel with sapphire lining

Mainspring barrel with sapphire lining

To reduce uneven friction within the mainspring barrel and facilitate ultra smooth winding, Romain has placed the steel mainspring between transparent synthetic sapphire plates.

Sapphire has a low coefficient of friction with steel making it the ideal material to use.

Bespoke balance wheel and triangular pallet lever

Bespoke balance wheel and triangular pallet lever

The regulator features the Romain Gauthier balance wheel with curved arms and calibrated eccentric weights, plus hand-assembled pallet lever that is triangular for maximum rigidity.

Gears with circular spokes, Logical One calibre, Romain Gauthier

Gears with circular spokes and high-efficiency teeth profiles

The distinctive gears feature circular spokes providing elegance and strength, while the patented, high-efficiency profiles of the gear teeth are designed for optimal contact.

Time setting, Logical One calibre, Romain Gauthier

Time-setting mechanism at 2 o’clock

In another subtle design touch, the crown and accompanying mechanism for setting the time
is at 2 oclock, instead of at 3 oclock,
to free up space for wrist movement.

S-Slot crew head, Logical One calibre, Romain Gauthier

S-slot screw heads

The signature screw heads bear an S-slot that not only is aesthetic, but also enables more torque to be applied during movement assembly.

Hand finishing, Logical One calibre, Romain Gauthier

Superlative hand-finishing

The spectacular movement decoration, which varies slightly from edition to edition, includes hand-created and hand-polished rounded bevels, hand-frosting, snailing, straight-graining and circular-graining, as well as hand-created and hand-polished jewel countersinks.

Learn about our other calibres