Mechanics

Complications

Tap parts of each dial to learn how the mechanism works.

Tap ⊕ to add up to 3 for comparison

1821 — Nicolas Rieussec

Chronograph

Measures elapsed time with start, stop and reset pushers.

Difficulty

●●●○○

Added parts

~125

Rarity

common

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How it works

A column wheel or cam coordinates clutches that engage the chronograph gear train with the seconds wheel.

Why collectors love it

Mechanical timing, a direct link to motorsport and aviation heritage.

Mini gallery

Column Wheel

The crown jewel — coordinates clutch and brake.

Heart Cam

Geometry that guarantees instant reset to zero.

Tachymeter

Bezel scale converts elapsed seconds to speed.

Famous examples

Omega SpeedmasterRolex DaytonaZenith El Primero

1954 — Rolex × Pan Am

GMT

Shows a second time zone via a 24-hour hand and bezel.

Difficulty

●●○○○

Added parts

~35

Rarity

common

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How it works

An additional wheel geared 2:1 against the hour wheel drives the 24-hour hand.

Why collectors love it

Essential for travelers; pioneered for transatlantic pilots.

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Pepsi Bezel

Red & blue — the original travel uniform.

Office GMT

Caller-style: GMT hand jumps, local hour fixed.

True GMT

Flyer-style: local hour jumps independently.

Famous examples

Rolex GMT-Master IIGrand Seiko SBGETudor Black Bay GMT

16th century

Moonphase

Displays the current phase of the lunar cycle.

Difficulty

●●○○○

Added parts

~12

Rarity

uncommon

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How it works

A 59-tooth wheel advances once a day, showing two moons through a half-disc aperture.

Why collectors love it

Poetic, astronomically accurate, deeply traditional.

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Bombé Moon

Hand-painted, gold-leaf stars on lacquered night.

Astronomical

Accurate to one day in 122 years on top calibers.

Double Aperture

Two moons share a 59-tooth eternal dance.

Famous examples

Patek Philippe 5396A. Lange Saxonia MoonphaseBlancpain Villeret

1762 — Thomas Mudge

Perpetual Calendar

Tracks day, date, month and leap year — correctly until 2100.

Difficulty

●●●●●

Added parts

~275

Rarity

grand

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How it works

A mechanical memory of cams and levers knows month lengths and leap cycles.

Why collectors love it

Among the most prestigious complications in watchmaking.

Mini gallery

48-Month Cam

Four years of memory on a single brass star.

Grand Lever

Reads the cam, jumps date 1–3 days at month-end.

Until 2100

Only needs correction at non-leap centuries.

Famous examples

Patek Philippe 5320GAP RO PerpetualLange Langematik Perpetual

1996 — Patek Philippe

Annual Calendar

Auto-corrects all months except February.

Difficulty

●●●○○

Added parts

~95

Rarity

uncommon

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How it works

A simpler cam system distinguishes 30 and 31 day months.

Why collectors love it

Most of the convenience, a fraction of the cost.

Mini gallery

One Setting / Year

Adjusts every March 1 — that's the only maintenance.

Triple Aperture

Day, date, month — Patek's 5396 signature layout.

Smart Cam

Knows 30 vs 31 — doesn't know leap years.

Famous examples

Patek Philippe 5396Lange Saxonia Annual

1933 — Breguet

Power Reserve

Shows remaining stored energy in the mainspring.

Difficulty

●●○○○

Added parts

~28

Rarity

uncommon

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How it works

A differential gear translates winding state into hand position.

Why collectors love it

Practical — know when to wind.

Mini gallery

Up / Down

Pocket-watch heritage display — F to E arc.

8-Day Movement

Twin barrels stretch reserve past a week.

Caseback View

Often shown on movement side for collectors.

Famous examples

A. Lange Lange 1Panerai Luminor PRIWC Big Pilot 7-day

1687 — Daniel Quare

Minute Repeater

Chimes the time on demand via tiny hammers and gongs.

Difficulty

●●●●●

Added parts

~340

Rarity

grand

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How it works

A slide arms snail cams that release hammers striking gongs for hours, quarters, minutes.

Why collectors love it

Acoustic artistry — the soul of haute horlogerie.

Mini gallery

Cathedral Gongs

Long, wrapped twice — deepest tone in horology.

Snail Cams

Three nested cams encode hours, quarters, minutes.

All-or-Nothing

Safety piece prevents partial chimes mid-strike.

Famous examples

Patek 5178GAP RO Concept RepeaterVacheron Patrimony Repeater

1801 — Abraham-Louis Breguet

Tourbillon

Rotates the escapement to average out gravity.

Difficulty

●●●●●

Added parts

~70

Rarity

grand

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How it works

Balance wheel and escapement sit in a cage rotating once per minute.

Why collectors love it

Pinnacle of mechanical artistry.

Mini gallery

Flying Tourbillon

Cantilevered cage — no upper bridge, unobstructed view.

Double-Axis

Cage within a cage — defeats gravity on two planes.

60-second Cycle

One full rotation per minute since 1801.

Famous examples

Breguet Classique TourbillonGreubel Forsey 24 SecondesAP RO Tourbillon