The Calibres

The wrong shape
for everything.

Watchmaking is built around the circle. Gear trains are round, balance wheels are round, repeater gongs want to be coiled circles. The Reverso is a rectangle that turns over — and the fifty-odd movements built to live inside it are the record of what happens when a house refuses to accept that as a limitation.

Fifty Movements, One Problem

Since 1931, Jaeger-LeCoultre has created around fifty different calibres for the Reverso alone — from the smallest mechanisms it makes to some of the most complicated, each one moulded to the shape of a watch that has to work upside down and back to front. What follows is not a spec sheet. It is the order in which the problems were solved.

I
1931 – 1933  ·  2 calibres

Borrowed Time

For its first two years the most famous rectangular watch in the world ran on somebody else’s movement.

Tavannes cal. 064
1931–1933
Manual · rectangular · bought-in
Reverso first series; Reverso De Luxe

The Reverso began life powered by a competitor, and the contract shows it was planned that way: Article 14 of the 1931 agreement expressly allowed movements from Tavannes, Movado or Jaeger/LeCoultre, while stating that a special movement “completely suited” to Chauvot’s case would follow. It had to. LeCoultre’s round calibres were too small for the rectangle and the Duoplan, its own finest shaped movement and the obvious candidate, was too thick. So Tavannes calibre 064 ran in the gentlemen’s watches and calibre 050 in the smaller ladies’ model, both without seconds, until about the end of 1932. Fritz calls it the one moment in the manufacture’s history when the maker of fine movements par excellence lacked the right calibre for its own watch.

The Duoplan (why nothing fitted)
1925
Two-storey architecture · large balance in a small movement
Not a Reverso calibre — the reason the Reverso needed Tavannes

The movement that explains the Reverso’s awkward first two years. Devised by Henri Rodanet, Jaeger’s technical director in Paris, and industrialised by LeCoultre at Le Sentier, the Duoplan stacked the movement across two levels (barrel and wheel train below, balance on the tier above), freeing space for a balance wheel far larger than a small movement could otherwise carry, and with it a precision nobody had managed at that size. It was radical, celebrated, and far too thick for Chauvot’s sliding case. So the watch that prefigured the Reverso’s spirit of rethinking received wisdom was the very movement that could not go inside it.

II
1933 – 1948  ·  4 calibres

The House Rectangles

Eleven different movements powered the pre-war Reverso. These are the ones that mattered.

LeCoultre cal. 11U / 410
from 1933
Manual · 15 jewels · 18,000 vph · ~50 h
Reverso with subsidiary seconds at 6

The movement the 1931 contract had promised: one “completely suited” to Chauvot’s case. Two years from problem to production movement is fast, which tells you how quickly the watch had succeeded, and it marked LeCoultre’s breakthrough, after almost a century as a barely-known maker of fine movements, into selling complete watches under its own name. Collectors can date a vintage Reverso quite precisely from the many small changes made to the calibre 11 family over the years. The modern cal. 822 was drawn, six decades later, to look deliberately like this one.

Cal. 413
1937
Manual · small seconds
Reverso 1937 small seconds

The manufacture’s fourth in-house Reverso movement, and a useful dating tool: watches carrying it have black dials signed Jaeger-LeCoultre (the first year the merged name appeared), which pins them precisely to 1937.

LeCoultre cal. 411
from 1933
Manual · centre seconds
Reverso with sweeping centre seconds

The 410’s twin, released simultaneously with a sweeping centre seconds hand instead of a subsidiary dial. Many variants followed; eleven distinct movements powered the Reverso before production stopped in the late 1940s.

Cal. 437/1 and P437/1
c.1947
Manual · centre seconds
Reverso “Interchangeable / Reversible”

The pair fitted to the late-1940s two-part-case Reverso, a little-documented variant in pink gold and steel with a centre seconds hand. Two consecutive examples surfaced together at auction in 2011, which is how the pairing of the 437/1 and P437/1 is known at all.

III
1972 – 1991  ·  6 calibres

The Movements That Came Back

A calibre borrowed from an oval watch restarted the whole line, and its descendant still runs the smallest Reversos made today.

Cal. 840 — “the Ovetto movement”
1972
Manual · oval
The 200-piece Corvo Reverso

The most consequential borrowed movement in the line’s history. When the manufacture told Giorgio Corvo it couldn’t build watches from 200 orphaned cases because there were no movements, he took the oval cal. 840 from the Ovetto, had a Milanese watchmaker build a spacer to seat it inside a Reverso case, and carried it back to Switzerland as proof. The Reverso exists today because an oval movement fitted a rectangular hole well enough to win an argument.

Cal. 846 / 846/1
late 1980s – today
Manual · 21,600 vph · 18 jewels · 93 parts · ~40 h
Reverso Classique, Lady, Classic Small, Reverso One 2026

An evolution of the calibre used in the Corvo revival, and one of the great survivors: tiny, thin, beautifully made, and still running the smallest Reversos in the current catalogue nearly forty years later.

Cal. 822
1991 – today
Manual · rectangular
Grande Taille, Ultra Thin Tribute to 1931, Classic Medium, Tribute Small Seconds, Hokusai enamels

Built for the larger Grande Taille case in 1991 and drawn to echo the 1930s cal. 410, a modern movement wearing a period face. It is now the workhorse behind some of the most beautiful watches in the line, including the enamel Tributes, where a thin, reliable, well-proportioned movement matters more than a complication.

Cal. 657 — the quartz years
1980s–2010s
Quartz
Reverso Classique, Reverso One (early), Reverso II

Easy to skip past, but part of the story: the Reverso came back from the dead in 1982 as a mostly quartz watch, and quartz kept it in the catalogue while the mechanical revival was rebuilt around it. The 657 ran the smaller Classique and the earliest Reverso One references before hand-wound movements displaced it.

Cal. 101 — the smallest of all
1929 – today
Manual · 98 parts · c.0.2 g · 21,600 vph
Reverso Joaillerie (c.1990); Grande Reverso 101 (2004)

Not designed for the Reverso, and older than it, but no list of its movements is complete without the 101. Introduced in 1929 and still made today, it remains the smallest mechanical movement ever put into series production: 98 components weighing about a fifth of a gram. In the jewellery Reversos the winding crown moves to the back of the case, because there is no room for it anywhere else.

Cal. 960, 970 and 977 — the automatics
1998 – 2012
Automatic
Gran’Sport; Grande Automatique; Squadra Hometime

The Reverso is overwhelmingly a hand-wound watch, for the obvious reason that a rotor adds height to a case that has to slide and turn. The exceptions came with the sportier families: the Gran’Sport of 1998 brought the first automatics to the line, and the Squadra and Grande Automatique carried them into the 2000s.

IV
1994 – today  ·  5 calibres

One Movement, Two Faces

The engineering problem that defines the modern Reverso: driving a dial on each side of a case that turns over.

Cal. 854 (854/1, 854A/2, 854C/2)
1994 – today
Manual · two dials · ~42 h
Duoface, Tribute Duoface, Classic Duoface, Fagliano

The defining modern Reverso movement. One gear train, two dials on opposite sides of a case that pivots: local time on the front, a second time zone on the back, no second movement, no compromise in thickness. Thirty years on it is still being reinterpreted rather than replaced.

Cal. 844 / 864 / 842 / 968
1994 – today
Manual · dual dial, women’s sizes
Duetto, One Duetto, Classic Duetto, Squadra Lady Duetto

The Duoface idea shrunk. The engineering challenge is the same but the tolerances are meaner: two dials driven by one movement inside a case narrow enough for a 2:1 rectangle. The 842 adds a moon phase; the 864A powers the Ultra Thin Duetto Duo.

Cal. 865 and 864
1997 – 2000s
Manual · dual dial, women’s
Reverso Duetto (1997); Ultra Thin Duetto Duo (864A)

The movements that made the Duetto work: the Duoface principle in a case narrow enough for a woman’s wrist, with a discreet dial for daytime and a decorative one for evening running off a single train.

Cal. 853 and 976
2016 – today
Manual · time only
Reverso Tribute Small Seconds; Grande Reverso 976

The plain hand-wound movements behind the simplest modern Tributes: no complication, nothing to display on the back, which is exactly the point when the case-back is meant to be left blank for the owner.

Cal. 965, 966, 968 and 969
2009 – today
Automatic and manual · women’s and mid-size
Squadra Lady Duetto; Reverso Classic Medium and Large

The workaday movements of the modern collection, the ones in most Reversos actually being sold, rather than the ones that get written about. The 968A drove the Squadra Lady Duetto; the 965 and 969 run Classic Medium and Large references today.

V
1991 – 2011  ·  12 calibres

The Complication Calibres

A rectangle is the wrong shape for almost every complication in watchmaking. That turned out to be the point.

Cal. 824
1991
Manual · power reserve · date
Reverso 60ème

The first complicated Reverso movement, and the first one JLC ever intended you to look at, the 60ème gave the watch a sapphire display back after sixty years of blank steel.

Cal. 828
1993
Manual · tourbillon · power reserve
Reverso Tourbillon

JLC’s first modern tourbillon, and it went straight into the hardest available case. A tourbillon wants a round plate; fitting the cage, the bridges and the going train into a rectangle without thickening the watch is most of the work.

Cal. 943 / 944
1994 / 2011
Manual · minute repeater
Répétition Minutes; Répétition Minutes à Rideau

The world’s first rectangular minute-repeater movement. Gongs are wound circles by nature; making them fit, and sing, in a rectangle is why almost nobody else tried. The 944 returned in 2011 with trebuchet hammers striking gongs fixed to the crystal itself.

Cal. 829
1996
Manual · retrograde chronograph · 36 jewels
Chronographe Rétrograde; Gran’Sport Chronograph (859)

A chronograph organised across two faces, using a retrograde hand that flies back to zero rather than sweeping a full circle, the rational answer to a rectangular dial. Its logic reappears in the 2023 cal. 860.

Cal. 879 / 873 / 874 / 875
2000–2003
Manual · double barrel · 8-day reserve · 28,800 vph
Septantième, Grande 8 Days, Sun Moon, Grande Date

Eight days of power from two barrels, married to a high-frequency balance, unusually long running time for a hand-wound watch this flat. The 879’s large-date architecture set up the entire Grande Reverso family, and its descendant cal. 834 powers the 2025 Tribute Geographic.

Cal. 855
2000
Manual · perpetual calendar
Reverso Quantième Calendrier Perpétuel

Leap-year indication on the front, month, day, date and moon on the back, a perpetual calendar split across a case that turns over, closing the six-watch anniversary series.

Cal. 823 and 823A
1999 – 2004
Manual · power reserve · moon phase · day/night
Grande Taille Sun Moon; Power Reserve (823A)

Three indications on one dial without crowding it: power reserve, moon phase, and a night-and-day display. The platinum Sun Moon it powered was capped at 125 pieces, the pink and white gold versions were standard production.

Cal. 858
1998
Manual · dual time · city selector · day/night both faces
Reverso Géographique (ref. 270.2.58)

The Reverso’s first true travel movement: a second time zone with a city-name selector on the reverse and day/night indication on both faces. World time then left the collection for twenty-seven years, until the calibre 834 brought it back in 2025.

Cal. 873, 874 and 875
2000 – 2003
Manual · 8-day double barrel · large date
Grande 8 Days, Grande Date, Sun Moon variants

The family that grew out of the Septantième’s 879: eight days of running from twin barrels, and the patented large-date display that gave the whole Grande Reverso line its identity.

Cal. 849 — the ultra-thin
1990s – today
Manual · 1.85 mm high · free-sprung balance
Reverso à Éclipses; Ultra Thin SQ skeleton

One of the flattest hand-wound movements in series production anywhere, and the reason certain Reversos can carry a shutter mechanism or a skeletonised dial without becoming thick. Where there is almost no room left, this is the movement that goes in.

Cal. 944
2011 · revised 2021
Manual · minute repeater · trebuchet hammers · crystal gongs
Répétition Minutes à Rideau; Tribute Minute Repeater (2021)

The 943’s successor, and the movement behind two of the most theatrical Reversos ever made. Its trebuchet hammers strike gongs fixed directly to the sapphire crystal rather than the case, which is what gives it its carrying voice. Revised again in 2021 with a silent regulator and a new generation of gongs.

Cal. 986
2009
Manual · dual dial · date · day/night
Grande Reverso Duo Date

A guilloché silver front with date at twelve and small seconds at six; a black reverse with luminous hands and a day/night indicator. Edition size is unsettled: an example at auction was numbered 286/500 against the 1,500 quoted elsewhere.

VI
2006 – today  ·  8 calibres

The Impossible Ones

Three dials. Four faces. A tourbillon spinning on two axes. Movements built because nobody had built them.

Cal. 175
2006
Manual · 3 displays · 18 functions · 6 patents
Grande Complication à Triptyque

The first movement ever to drive three dials: front, back, and a third set into the cradle the case pivots within. Civil time, sidereal time and perpetual calendar simultaneously, plus a tourbillon and an equation of time, from a single going train.

Cal. 174 — Gyrotourbillon 2
2008
Manual · spherical multi-axis tourbillon · cylindrical hairspring
Reverso Gyrotourbillon 2

Two carriages rotating on different axes (the inner one turning once every 18.75 seconds, the outer once a minute) inside a rectangle. It was the first wristwatch to use a cylindrical hairspring, and it won first and second place at the 2009 International Chronometry Competition.

Cal. 179 — Tribute Gyrotourbillon
2016
Manual · bi-axial flying tourbillon · Gyrolab balance
Reverso Tribute Gyrotourbillon; Hybris Artistica

The Gyrotourbillon shrunk by roughly a third in width and thickness versus 2008, now flying, with nothing bridging it from above, and with a hemispherical balance spring and the deliberately non-circular Gyrolab balance wheel, shaped to cut air resistance.

Cal. 185 — Quadriptyque
2021
Manual · 4 faces · 11 complications · 12 patents
Hybris Mechanica Cal. 185 Quadriptyque

The most complicated movement ever fitted to a Reverso, and the only one in history to drive four working display faces. Perpetual calendar and flying tourbillon; minute repeater with a digital jumping hour; and three lunar cycles (synodic, draconic and anomalistic) displayed in the cradle.

Cal. 826
2021
Manual · digital jumping hour · moon phase · day/night
Reverso Tribute Nonantième

Built new for the 90th anniversary to do something the case-back had never done: a semi-jumping digital hour beside a rotating minute disc and a day/night indicator, a second complication on the reverse rather than a repeat of the front.

Cal. 953
2025
Manual · integrated minute repeater · 7 patents
Reverso Tribute Minute Repeater

A wholly new integrated repeater movement, open-worked so the striking train is the view, with seven new patents. Thirty-one years after the world’s first rectangular repeater, the problem is evidently still interesting.

Cal. 860
2023
Manual · chronograph · 300+ parts · double-sided
Reverso Tribute Chronograph

Takes its cue from the 1996 cal. 829 and integrates a chronograph with a double-sided time display, over 300 components in a case under 12 mm thick.

Cal. 834
2025
Manual · world time · Grande Date (patented)
Reverso Tribute Geographic

A descendant of the 8-day 879, re-engineered to put world time into a rectangle for the first time since 1998, with a patented large-date display that had defeated earlier attempts at this size.

Still Being Written

Two new calibres in the last two years.

Cal. 953 in 2025 earned seven patents; cal. 834 finally put world time in a rectangle. The hardest problems in this collection are evidently still open.

See the Models