Mechanics

Movements

How watches keep time.

Quartz

±15 sec / month

Battery-powered precision.

A small battery sends current through a quartz crystal, which oscillates 32,768 times per second. A circuit converts the pulses into one tick per second.

Pros

+ Extremely accurate
+ Affordable
+ Low maintenance

Cons

− Battery changes
− Lacks mechanical romance

Automatic

−4 / +6 sec / day (COSC)

Wound by your wrist.

A weighted rotor swings with wrist motion, winding the mainspring. Stored energy flows through gears to the escapement, which releases it in precise beats.

Pros

+ No battery
+ Self-winding
+ Mechanical craft

Cons

− Needs servicing
− Less accurate than quartz

Manual Wind

±5–10 sec / day

A daily ritual.

Turning the crown winds the mainspring directly. There is no rotor, so the movement can be thinner — a favorite for dress watches.

Pros

+ Thin profile
+ Direct connection
+ Pure mechanics

Cons

− Must be wound regularly
− No power if forgotten

Tourbillon

±2 sec / day (top tier)

Gravity, defeated.

Invented by Breguet in 1801, the tourbillon places the escapement and balance wheel inside a rotating cage to average out gravity's effects on accuracy.

Pros

+ Mechanical artistry
+ Improved accuracy in pocket era
+ Status symbol

Cons

− Extremely expensive
− Marginal benefit on wrist

Chronometer

−4 / +6 sec / day

Certified precision.

Not a movement type but a rating. A chronometer has passed COSC's 15-day, multi-position, multi-temperature accuracy test.

Pros

+ Verified accuracy
+ Quality assurance

Cons

− Adds cost
− Not all good movements bother

Spring Drive

±1 sec / day

Mechanical heart, quartz brain.

Seiko's hybrid winds like an automatic but regulates with a tri-synchro tuned by a quartz oscillator. The seconds hand glides without ticking.

Pros

+ ±1 sec/day accuracy
+ Glide motion seconds
+ No battery

Cons

− Proprietary to Seiko/Grand Seiko
− Costly