22k gold, cut in sunray
Swings with your wrist and winds the mainspring in both directions. Weighted at the rim, so a slow morning still counts.
Free-sprung, beating at 3 Hz
Regulated in six positions over nine days, then signed off by the watchmaker who assembled it.
One block of sapphire
Milled for 212 hours and polished until you can read the calibre straight through the lugs.
Forty turns to full
Fluted steel, the one part you touch every morning. Wind it and the reservation rail opens below.
Open the railCalibre HV-31 · Sapphire · 120 pieces
The back is
the better side
A self-winding calibre in a case milled from a single block of sapphire, so nothing we made is hidden from you.
Scroll to turn it over, move your hand to lean inScroll to turn it over, drag sideways to lean in
We spent four years on the side most watches hide.
Iris Vane, head of movement, Vallée de Joux
Exploded view
Four layers, nothing painted on
- 01
Caseback crystal
1.2 mmSapphire, anti-reflective on the inside only, so a scratched outside never fogs the view.
- 02
Rotor
22k22k gold on a ceramic bearing. The sunray is cut by hand in eleven passes.
- 03
Calibre HV-31
23 jewelsFlame-blued screws, bridges bevelled with a pegwood stick, balance cock engraved with the maker's initials.
- 04
Monobloc case
212 hOne sapphire block, no visible gaskets, nothing painted on to hide a join.
The complications, in figures
Everything it does, and nothing more
- Movement
- HV-31, self-winding hand-wind by crown
- Frequency
- 21,600 vph 3 Hz
- Power reserve
- 72 h 40 crown turns from empty
- Rate
- −2 / +4 s per day six positions
- Jewels
- 23 ruby, domed
- Functions
- Hours, minutes, small seconds
- Case
- 40.5 × 11.2 mm monobloc sapphire
- Water resistance
- 30 m 3 bar
- Edition
- 120 numbered pieces 14 a year
The atelier
One watchmaker, one watch
Every HV-31 is assembled, regulated and cased by the same pair of hands, and their initials are engraved under the balance cock where only the next watchmaker will ever read them. It takes nine weeks. We finish fourteen a year.