annual calendar

What is an annual calendar?

An annual calendar is able to accurately display the number of days in every month except February. Therefore, it needs to be adjusted only once per year on March 1st.

How is Ludwig Oechslin’s annual calendar unique?

Oechslin executes his annual calendar as a gear system using only the following custom-designed parts:

• Dial that serves as a module in the gear system (left)
• Month disk and cog with 5 teeth, double-toothed (center top)
• Collar with two fingers bonded to the hour rod (center)
• Weekday disk (center bottom)
• Date ring (right)

The month, date and weekday indications are actually inscribed directly on the front-side of the functional parts  –  an annual calendar can’t be reduced further (diagram).

How does it work?

Two additional fingers are bonded to the hour rod which drives the weekday disk and, via the 5 longer teeth on the month disk, imparts an extra impulse to the month disk on months with 30 days or less (February). The month disk receives power from the toothed date ring via the 5 tooth cog.

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 weekday in analog fashion, like the hands on a watch. An analog display is more readable than a digital display or alphanumeric characters displayed in a window on the dial. Gears also allow the annual calendar function to be executed using very few parts. Fewer parts leads to higher reliability of the functions  –  and easier servicing. It’s why ochs und junior can offer a lifetime guarantee on the parts designed by Ludwig Oechslin. Finally, Oechslin’s gear system enables the date to be adjusted quickly via the crown; there is therefore no need for additional pushers like in conventional annual calendars. Oechslin enjoys the intellectual challenge of designing watches in the most technically elegant and functional manner possible.

An annual calendar watch accounts for months with 30 or 31 days. The date therefore only requires manual adjustment once per year on March 1st. Conventional annual calendar watches display the date, month and weekday using text and numbers. They use levers and springs and comprise many parts (Patek Philippe’s uses 154). Oechslin invested 3 years in developing a new annual calendar function comprised of just 3 additional parts (see video), because fewer parts imply fewer interactions between parts and higher reliability. All functions can easily be set using the crown.

Your annual calendar

ochs und junior manufactures about 40 annual calendar watches per year. You can select your annual calendar from models designed by ochs und junior in our online store. Or you can design your annual calendar using our online customizer. We are available by phone, email, or in person to offer guidance in selecting your perfect annual calendar watch.

Dimensions

42mm x 11mm (incl. crystal)
39mm x 11mm
36mm x 11mm
Print 1:1 (PDF)

Weight

42mm titanium: 70g (incl. sturgeon leather strap and buckle)
39mm titanium: 62g
36mm titanium: 53g

42mm sterling silver 925: 109g
39mm sterling silver 925: 101g
36mm sterling silver 925: 93g

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.

The case of the annual calendar LIGHT is machined differently. More information here.

Base Movement

ETA 2824-2 with 38 hours of power reserve. Manufacturer: ETA SA / Grenchen / Switzerland.

Crown

Screw-down crown designed by Ludwig Oechslin (39mm and 42mm). Manufacturable on the right or left side of the case. Available in grade 5 titanium or sterling silver 925; other materials upon request. In 36mm the crown is not screw-down, however all sizes have the same water resistance rating. Manufacturer: Pibor SA / Glovelier / Switzerland.

Buckle

Buckle for leather strap: 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. The design of the buckle differs slightly for a 42mm and a 39mm case and matches the lugs.

Buckle for rubber strap: Classic buckle, designed by Ludwig Oechslin. Visible machining marks. Grade 5 titanium or sterling silver 925; additional materials upon request. The design of the buckle differs slightly for a 42mm and a 39mm case and matches the lugs.

Buckle for textile strap: Carbon fiber buckle designed by Ludwig Oechslin for use with the textile strap, fastened with Velcro.

Watch straps

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

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 annual calendar watch is entirely manufactured in Switzerland. 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 small scale and direct sales model allow it to offer uniquely fast and competent service.

Designed by ochs und junior

Watches in the annual calendar store 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. We are also happy to discuss ideas which are not in the customizer with you. Please contact us for a personal consultation.