annual calendar

Month, date, weekday and time.

Overview

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 have annual calendar functions which are implemented using levers and springs and comprise numerous parts (Patek Philippe’s uses 154).

Ludwig Oechslin

Dr. Ludwig Oechslin designed his annual calendar watch to be functional. As he explains in this video, he chose to display the date with analog dots in order to put the time at the top of the watch’s visual hierarchy, and make the date readable from the same distance as the time. Dr. Oechslin invested 3 years developing a new annual calendar function comprising just 3 additional parts, because fewer parts mean fewer interactions between parts and higher reliability. All functions can be set simply using the crown.

The interactive watch below shows how to read the functions, and you can learn about how the function works in the “Mechanics” section. Detailed technical information is available at the bottom of this page.

Your annual calendar

ochs und junior manufactures about 50 annual calendar watches per year. Each watch is sold directly by cofounder Beat Weinmann from the ochs und junior workshop in Lucerne. 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. With pleasure, Weinmann will guide you to your perfect annual calendar watch on the phone, over email, or in person.

Swiss made

The ochs und junior annual calendar watch is entirely manufactured in Switzerland. The case, gear system, dial, buckle, and hands are individually-manufactured by Peter Cantieni in Hinwil, Switzerland. Each watch is hand-assembled and regulated by Romana Fux to 0/+5 seconds at the ochs und junior workshop in Lucerne.

Lifetime warranty

A lifetime warranty covers all parts invented by Dr. 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.

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Reading the functions

The arrows next to the watch above allow you to show different dates. Reading Dr. Oechslin’s calendar becomes intuitive after a short time on the wrist.

Date

The 30+1 holes around the perimeter of the dial display the date. The 10 minute markers serve as reference points. For example: the marker indicating 30 minutes also shows the 15th day of the month (30÷2=15). These 5 day markers allow for the date to be read at a glance and after a short time, you can recognize the date intuitively. The date only needs to be adjusted once per year on March 1st.

Weekday

The 7 holes display the weekday (counterclockwise rotation). You can choose which weekday you would like to display at the top. The interactive watch above is set to Sunday.

Month

The 12 holes display the month (counterclockwise rotation).

Day/night

One visible weekday dot indicates daytime (6am to 6pm). Two visible weekday dots indicate night time (6pm to 6am). This indication is not shown on the interactive watch above.

Time

The exact minute and second can be read using the date holes, which are spaced at 2 minute intervals. Holes mark even minutes and gaps odd minutes. The holes and gaps are exactly the same width as the minute hand.

Ludwig Oechslin’s annual calendar function in brass.

Mechanics

What is an annual calendar?

An annual calendar knows the number of days in every month except February. The date therefore only needs adjustment once per year on March 1st. Annual calendars are generally executed with levers and springs using a large number of parts (Patek Philippe uses 154).

How is Dr. 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. Further information is available directly from Ludwig Oechslin.

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.

Technical information

Dimensions

42mm x 11mm or 39mm x 11mm (incl. crystal)

Weight

42mm titanium: 70g (incl. sturgeon leather strap and buckle)
42mm sterling silver 925: 109g
42mm titanium LIGHT: 42.94g (incl. textile strap and carbon buckle)

39mm titanium: 62g
39mm sterling silver 925: 101g
39mm titanium LIGHT: 39.97g (incl. textile strap and carbon buckle)

Water resistance

50m in titanium, 30m in sterling silver 925. Both models are fit for almost any situation in daily life. For swimming, we recommend titanium.

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. Manufacturer: Peter Cantieni / Hinwil / Switzerland.

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

Base Movement

ETA 2824 with 38 hours of power reserve. Hand-regulated by ochs und junior watchmaker Romana Fux to 0/+5 seconds per day. Manufacturer: ETA SA / Grenchen / Switzerland.

Crown

Screw-down crown designed by Ludwig Oechslin. Manufacturable on the right or left side of the case. Available in grade 5 titanium or sterling silver 925; other materials upon request. Manufacturer: Pibor SA / Glovelier / Switzerland.

Buckle

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. Manufacturer: Peter Canieni / Hinwil / Switzerland.

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. Manufacturer: Peter Canieni / Hinwil / Switzerland.

Textile strap: Carbon fiber buckle designed by Ludwig Oechslin for use with the textile strap, fastened with Velcro. Manufacturer: Peter Canieni / Hinwil / Switzerland.

Watch straps

We offer over 80 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.

Night visibility

To assure optimal readability of the time at night, we use Super-LumiNova X1. This coating is manufactured by RC TRITEC in Teufen / Switzerland. In principle, all Pantone colors can be made. Super-LumiNova is always applied in conjunction with a color pigment. The brighter the color, the better the luminosity. At night, 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 watchmaker Romana Fux, or for dials with a color application by Cador in Eimeldingen / Germany and by Monyco in La Chaux-de-Fonds / Switzerland.

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 cofounder Beat Weinmann for a personal consultation.