perpetual calendar

How is Ludwig Oechslin’s perpetual calendar function unique?

Oechslin executes his perpetual calendar as a gear system comprising 9 additional parts and 3 modified parts (*).

1. Dial*
2. Month disk
3. Date disk*
4. Baseplate for perpetual calendar mechanism
5. Date ratchet wheel
6. Bridge
7. 4 year ratchet wheel
8. Another bridge
9. In-between wheel
10. 12-hour ratchet wheel*
11. Month ratchet wheel
12. Additional tooth

Each part is designed to solve multiple problems at once. Like in software engineering and architecture, a simpler solution is more difficult to achieve, but technical elegance brings significant benefits. If a solution requires fewer parts, there are fewer interactions between parts, and fewer potential sources of manufacturing error. Oechslin strives to develop the simplest possible solution because he wants a more reliable result – and he enjoys the intellectual challenge. His ability to reduce a perpetual calendar down to 9 additional parts is the only way ochs und junior, a company with 4 employees, could bring to market an original perpetual calendar function. Oechslin replaces the R&D and quality assurance departments with greater upfront thinking.

What was Oechslin’s motivation for using gears?

With their turning wheels, gears lend themselves to Oechslin’s goal of displaying the date, month and year in analog fashion, like the hands on a watch. The calendar information on Oechslin’s perpetual calendar is readable from the same distance as the time. Gears also allow Oechslin to invent solutions which use fewer parts. Fewer parts leads to higher reliability – and easier servicing. It’s why ochs und junior can offer a lifetime guarantee on the parts designed by Oechslin. Finally, his gear system enables all of the functions to be adjusted quickly via the crown; there is therefore no need for additional pushers like in conventional perpetual calendars. It is fun to set! Check out the “Forwards and backwards” video.

What is the base movement?

The Ulysse Nardin UN-118.

Who is Ludwig Oechslin?

The ochs und junior perpetual calendar is the result of Ludwig Oechslin’s 40 year watchmaking career, during which he has continually returned to the challenge of displaying and implementing calendar watches. In the 1990s, Oechslin invented the first perpetual calendar watch with a date adjustable in both directions, the Ulysse Nardin Perpetual GMT.

A perpetual calendar watch accounts for leap years and displays the correct date until the year 2100. Conventional perpetual calendar functions are executed in levers and springs, are delicate to handle, and comprise many parts (Patek Philippe uses 182). The date is usually only adjustable in one direction via pushers on the sides of the case.

Ludwig Oechslin

Ludwig Oechslin’s perpetual calendar watch is designed to be practical – from its unique date display to the simplicity with which it can be set. As he explains in this video, the date is displayed with analog dots so that it can be read from farther away than with numerical indications, and to keep the time the first information in the watch’s visual hierarchy. Oechslin’s perpetual calendar function is executed in just 9 additional parts, because fewer parts mean fewer interactions between parts and higher reliability. The date is adjustable both forwards and backwards, and every function can be set simply using the crown.

Your perpetual calendar watch

ochs und junior manufactures about 15 perpetual calendar watches per year. You can select your perpetual calendar watch from models designed by ochs und junior in our online shop. Or you can design your perpetual calendar using our online customizer. With pleasure, we will guide you to your perfect watch on the phone, over email, or in person.

Dimensions

42mm x 12.5mm (incl. crystal)

Weight

76.4g in titanium (incl. leather strap and buckle)
119.1g in sterling silver 925 (incl. leather strap and buckle)

Water resistance

100m in titanium, 100m in sterling silver 925. Both models are fit for almost any situation in daily life.

Case

2-part case designed by Ludwig Oechslin. Available in grade 5 titanium or sterling silver 925; additional materials upon request. Visible machining marks. ochs und junior watches require no movement ring due to the extremely small manufacturing tolerances on the case. Available exclusively with a solid case back.

Base movement

Ulysse Nardin UN-118 with 60 hours power reserve. Manufacturer: Ulysse Nardin SA / Le Locle / Switzerland.

Crown

Screw-down crown designed by Ludwig Oechslin in grade 5 titanium or sterling silver 925. Manufacturers: Pibor SA / Glovelier / Switzerland and Helfenstein Mechanik AG / Alpnach / Switzerland.

Buckle

Designed by Ludwig Oechslin for 22mm watch straps with no loops. Visible machining marks. Grade 5 titanium or sterling silver 925, additional materials upon request. Manufacturer: Helfenstein Mechanik AG / Alpnach / Switzerland.

Watch straps

We offer many possibilities, which you can explore in our straps pages: sturgeon, leather, suede, rubber.

Sapphire crystal

The sapphire crystals are manufactured by Stettler in Lyss / Switzerland. Both sides are treated with anti-reflective coating by Econorm in St-Imier / Switzerland.

Reading the time in low-light or dark conditions

For optimal readability our watches are coated in Super-LumiNova X1, manufactured by RC TRITEC in Teufen / Switzerland. Super-LumiNova is always applied in conjunction with a color pigment. All Pantone colors are available, but the brighter the color, the better the luminosity. Super-LumiNova shines green (the option used by ochs und junior) or blue, on special request. The Super-LumiNova coating is applied by hand by ochs und junior, or for dials with a color application by Cador in Eimeldingen / Germany and by Monyco in La Chaux-de-Fonds / Switzerland.

Swiss made

The ochs und junior perpetual calendar is entirely manufactured in Switzerland. The Ulysse Nardin UN-118 base movement is manufactured in Le Locle. Each watch is hand-assembled and regulated at the ochs und junior workshop in La Chaux-de-Fonds.

Lifetime warranty

A lifetime warranty covers all parts invented by Ludwig Oechslin, and the entire watch is covered by a 2-year guarantee. ochs und junior’s limited production and direct sales model allows us to offer uniquely fast and competent service.

Designed by ochs und junior

Watches in the perpetual calendar shop are designed by ochs und junior. Individually manufactured, they have the potential to become classics.

Custom-made

Ludwig Oechslin’s rigorously simple designs, the fact that we individually manufacture our parts, and the direct contact we have with our clients enable us to offer the highest possible degree of customization. The customizer shows many possibilities.