anno-annual calendar
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Reading the functions
The arrows next to the watch above allow you to show different dates. Reading Oechslin’s calendar quickly becomes intuitive.
Date
The 30+1 holes around the perimeter of the dial display the date with 10-minute markers serving 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 intuitively. The date only needs to be adjusted once a 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 module in brass.
Mechanics
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. 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.
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 use levers and springs and comprise many parts. 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.
Further information
Dimensions
42mm x 11mm (incl. crystal)
Weight
42mm titanium: 70g (incl. leather strap and buckle)
Water resistance
100m in titanium
Case
2-part case in grade 5 titanium, designed by Ludwig Oechslin.
Base Movement
ETA 2824-2 with 38 hours of power reserve. Manufacturer: ETA SA / Grenchen / Switzerland.
Crown
Screw-down crown designed by Ludwig Oechslin in grade 5 titanium.
Buckle and strap
Classic buckle in grade 5 titanium, designed by Ludwig Oechslin. Visible machining marks. Ecopell leather strap in dark blue, “Enzian”, or black in S/M/L/XL, handmade by Sabina Brägger.
Crystal
Sapphire crystal.
Night visibility
Swiss Super-LumiNova, applied by Monyco in La Chaux-de-Fonds/Switzerland.
Swiss made
The ochs und junior ochs line anno is entirely manufactured in Switzerland. Each watch is hand- assembled and regulated at the ochs und junior workshop in La Chaux-de-Fonds.
Warranty
The entire watch is covered by a 2-year guarantee.
Design
Ludwig Oechslin, non-customizable.
Order
Order via Mail oj@ochsundjunior.ch or via our homepage (shop).
Order with a 50% prepayment in accordance with the ochs und junior standard guidelines:
Payment via our homepage (stripe) or via bank transfer to our bank account:
Credit Suisse, Schwanenplatz 8, CH-6002 Luzern
ochs und junior AG
IBAN: CH31 0483 5039 2684 4100 0
Clearing No. 4835
Swift: CRESCHZZ80A
Account No. 0463-392684-41