A "mechanical wonder" created by the long-established Le Sentier: Jaeger-LeCoultre "Reverso Hybris Mechanica Caliber 185"

Jaeger-LeCoultre has long been a leader in the complicated watch market. After a brief lull, they've returned in 2021 with a spectacular new piece. The new Reverso Hybris Mechanica Calibre 185 is an unprecedented masterpiece, featuring 11 mechanisms across four sides. But what's noteworthy about this watch is not just its incredible functionality, but the exceptional skill of the long-established company in bringing it all together in a usable size.

The accumulation of small details
A "small" size that is unusual for a super complicated watch

　Since the 1990s, Jaeger-LeCoultre has been working on producing complicated watches. The material they chose was the Reverso, which was considered outdated at the time. Taking advantage of the inverted case that protected the crystal, the company added various displays to the back of the case. Each year, the Reverso became more complicated, culminating in the creation of the Reverso Hybris Mechanica Calibre 185. With 11 different mechanisms across four dials, this is the company's most complex supercomplication to date.

　It would take too much space to describe the full scope of this watch, which features a tourbillon, instantaneous perpetual calendar, grand date, day of the week, month, leap year, day/night indicator, digital jumping hours, minutes, minute repeater, northern hemisphere moon phase, nodal lunar cycle (position of the moon), periapsis lunar cycle (apogee and perigee), month, year, and southern hemisphere moon phase. What I want to emphasize here is that it manages to pack all of these functions into a usable size.

　The perpetual calendar is not controlled by the standard 48-month cam, but by two layers: a 12-month cam and a 4-year cam. This not only makes the perpetual calendar mechanism smaller horizontally, but also makes it easier to adjust the calendar. Furthermore, the instantaneous calendar and the moon phase display on both sides of the cradle (base) are operated by torque accumulated over 24 hours. Therefore, Jaeger-LeCoultre explains, the balance wheel's amplitude does not decrease at all when the calendar is switched.

　The repeater was also designed with great ingenuity. Packed with so many features, this watch lacked the space to accommodate a repeater. Therefore, a trebuchet hammer, with a bendable tip, was used. Despite its small size, this increased the hammer's inertia made it easier to make a louder sound. Also, unlike existing repeaters, the snail, which determines the number of times the repeater sounds, now reads the information that it will not operate if the gong is not struck. Therefore, if the quarter-minute sound is not sounded, the cam that engages with the snail will not move. This is why the sound continues seamlessly—hours, quarter-minutes, minutes. Additionally, by using a snail that reads the time every hour, we were able to successfully add jumping hours to the remaining space.

　Just like previous Hybris Mechanica models, all information, such as the moon phase and year displays on both sides of the cradle, is switched once every 24 hours simply by a protrusion that pops out from the movement. Not only are all four displays on both sides of the cradle, as well as the year and month displays, switched with just one input per day, but the moon phase display is also incredibly accurate, with only a one-day error every 1111 years. Increasing the number of gears or teeth would make the moon phase display more accurate, but this would require the cradle to be made larger and thicker. Jaeger-LeCoultre only explains that "by making the gears long and precise, we were able to make the mechanism inside the cradle thinner," but this is surely the pinnacle of Jaeger-LeCoultre's expertise as a "movement maker."

　The grand date, placed next to the tourbillon carriage, has also been made compact. By doubling the "1" display in the ones place, the disc in the ones place has been successfully made smaller. It may seem simple, but these small details have succeeded in keeping this ultra-complicated watch at a "small" size of 51.2mm in height, 31mm in width, and 15.15mm in thickness. Safety has also been taken into consideration. When removed from the cradle, only the hands can be set, so there is no need to worry about accidentally moving the mechanism. The repeater does not have a safety mechanism, but "there is no time lag, so it is unlikely that it would be operated while it is running."

　The long-awaited release of the Reverso Hybris Mechanica Calibre 185 is a design that shows no sign of years of silence, a testament to the long-established Le Sentier brand. Jaeger-LeCoultre has finally returned to the world of haute horlogerie with this masterpiece.