ochs und junior Bring the Incredible Day/Night to the Ochs Line

We’re huge fans around here of ochs und junior, an independent brand known for radically simple executions of complications that are traditionally anything but. Their latest is a release of one of their most whimsical and complex pieces, the Day/Night, which was first seen in 2018 but now enters the “ochs line,” meaning it gets a standardized, serialized production, without the vast array of customization options offered on most watches in the brand’s catalog. That said, considering the astronomical nature of the complication, some custom work is required, so the Day/Night really splits the difference. Even more than ochs und junior’s fairly radical calendar watches, the Day/Night really shows off the ingenuity at work behind Ludwig Oechslin’s watchmaking. 

Looking at the dial, it’s hard to grasp at first exactly what you’re seeing. The time, of course, but the rest of the indicators are so far removed from what we’re used to seeing on a watch, the Day/Night really does require something of a primer to fully grasp. Here’s what you can see at a glance on the dial: the length of day and nighttime for a given location, sunset, sunrise, solar noon, moon phase, sun and moon position in the sky, the date, and of course the current time. Much of this information is dependent on the wearer’s current location, so in the ordering process, ochs und junior make a note of where the watch will live, and create a custom part to “synch” the watch to that location. The brand can make a new part in the event a client moves, and the watch can be made to work in either the northern or southern hemisphere. 

So, how do you read the thing? Day and night are indicated by the light and dark areas that surround the dial. The lines that separate these sections represent the horizon, which seems fairly intuitive. As you can see in a demonstration video below, the horizon lines change position every 10 days to account for the changing of seasons (fast forward to 2:11 and you’ll see that day and night are split 50/50 at the Spring Equinox). When the watch is set correctly, the sun in the outer ring passes from the darker “night” area to the lighter “day” side at sunrise, and the process reverses in the evening. The moon phase is read by observing the moon’s position as it relates to the sun – it’s beneath the sun at a new moon, and directly above it when the moon is full. Solar noon is relatively straightforward, and can be set with the pusher at 6:00 by “holding” the sun at the time of day when it’s at its highest position in the sky. Lastly, the sun and moon position can be determined by facing south when wearing the watch, and observing where the sun and moon indicators are sitting on the dial. If the watch is set correctly, they’ll point to each. 


Obviously, this is a ton of information, represented in a poetic and artistic way. It’s not necessarily as practical (if that’s even the word we should be using) as some other watches with similar astronomical complications that might be more intuitive, but part of the appeal here is the economy of the movement. From a humble Ulysse Nardin UN-320 base movement, a total of 13 parts are added to create the Day/Night. And that includes the dial (which has a mechanical component built into it for the horizon indicator). 

The version seen here, with a 40mm titanium case and multi-tone dial that includes a brass ring representing the day with corresponding hands, and a dark blue metallic section that is meant to shift in color with the light, is available to order from ochs und junior now. The retail price is CHF 10,700. ochs und junior

Images from this post:
Related Posts
Zach is a native of New Hampshire, and he has been interested in watches since the age of 13, when he walked into Macy’s and bought a gaudy, quartz, two-tone Citizen chronograph with his hard earned Bar Mitzvah money. It was lost in a move years ago, but he continues to hunt for a similar piece on eBay. Zach loves a wide variety of watches, but leans toward classic designs and proportions that have stood the test of time. He is currently obsessed with Grand Seiko.