moon phase trilogy

moon phase special chinese


This summer ochs und junior is celebrating its 15th anniversary. As part of our anniversary celebration, we are pleased to present a special edition ochs und junior moon phase. It will only be available by pre-order from May 1st to January 31st 2022.

The 39mm moon phase will come in three different variations: the first watch with a black galvanized dial and red lacquered moon disk with red markers and hands and a case made out of Titanium grade 5 black PVD coated. The second with a red lacquer-coated dial with black galvanized moon disk, black markers and hands, and third, an emerald-green lacquered dial with black galvanized moon disk, and golden markers and hands. The emerald green watch will feature a jade-stone as the sun at the 12 o’clock position. The second and third watch have a case made out of Titanium grade 5. The straps are made from Red or Black Textile with a titanium grad 5 buckle. This edition is not customizable. The watches can be purchased individually or as a trilogy (single price incl. 7.7% VAT CHF 8000, CHF 7400 export price; trilogy: CHF 22,000 incl. 7.7% VAT, export price 20,300).

Pre-orders to [email protected] are accepted upon prepayment of 50% of the purchase price according to our ochs und junior purchase guidelines. Watches ordered and paid before June 30th can be delivered in time for the Moon Festival on September 21st.

moon phase special black galvanic dial ochs und junior

moon phase black galvanic

moon phase trilogy red special ochs und junor

moon phase red lacquered


moon phase emerald jade

Reading the functions

Moon phase

The center represents earth and the large dot at 12 o’clock represents the sun. Full moon is when the moon is opposite the sun and earth at 6 o’clock. New moon is when the moon is hidden between the sun and earth at 12 o’clock. The new moon is represented by a dark circle at 6 o’clock.


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. This video of Ludwig Oechslin explaining the date spiral for his perpetual calendar is also relevant for his moon phase watch.


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.


How is Oechslin’s moon phase function implemented?

An epicyclic gear train driven by a central finger bonded directly to the hour pipe turns the lunar disk beneath the dial counter-clockwise. The central finger engages with a wheel bearing 12 teeth, whose pinion with 14 teeth meshes with a wheel bearing 18 teeth, whose pinion with 14 teeth meshes with the fixed recessed ring gear with its 109 teeth machined into the underside of the dial (annotated diagram).

What is the benefit of a highly precise moon phase calculation?

The average time between two identical moon phases is 29.530589 days. Most moon phase watches approximate a lunation as 29.5 days, which leads their calculation to be off by 1 day after 2 years. The closer your moon phase calculation comes to the average lunation of 29.530589 days, the “flatter” the difference between your prediction and the actual moon phase. The ochs und junior moon phase calculates the lunation as 29.5306122449 days. As a result, it will predict the moon phase correctly for 3,478.27 years before it is off by 1 day. This means that you only have to set your moon phase one time, and you can trust that its prediction is precise.

Watches and astronomy by Ludwig Oechslin.

Further Information


39mm x 11mm


Titanium: 62g

Water resistance

100m in titanium.


2-part case designed by Ludwig Oechslin. Available in grade 5 titanium or grade 5 titanium black PVD coated. Visible machining marks. ochs und junior watches require no movement ring due to the extremely small manufacturing tolerances on the case.

Moon phase function

5-part epicyclic gear system designed by Ludwig Oechslin. The calculation is precise for 3,478.27 years before it is off by one day.

Date function

30+1 hole date spiral with 5 minute markers that serve as reference points designed by Ludwig Oechslin.

Base movement

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


Screw-down crown designed by Ludwig Oechslin (39mm). Available in grade 5 titanium. Manufacturer: Pibor SA / Glovelier / Switzerland.


Grade 5 titanium. The design of the buckle differs slightly for a 39mm case and matches the lugs.

Watch straps

We offer over 80 possibilities, which you can explore in our straps pages: sturgeonleathersuederubber.


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

Swiss made

The ochs und junior moon phase 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 moon phase trilogy shop are designed by ochs und junior. Individually manufactured, they have the potential to become classics.