Experience Grand Seiko and discover The Spirit of Takumi with our concierge by emailing Boutiques.USA@grand-seiko.us.com





The concept of Grand Seiko was born from the desire to build the world's best watch, and the collection continues to push precision in mechanical watches to the limits of timekeeping technology.

As a true manufacture, Grand Seiko incorporates the latest technology alongside its breadth of craftsmanship to raise the art of watchmaking to its peak.

With anywhere between 200 and 300 individual parts, mechanical watches must exhibit a near-perfect consistency of functionality in the detail of these parts to ensure the precision of the movement. Seiko employs Micro Electro Mechanical Systems (MEMS) technology in the manufacturing of its escapements, bringing the mechanical accuracy of its parts to the forefront of technology.
Mere parts alone, however, cannot constitute the level of precision for which Grand Seiko is renowned.

The task of assembling Grand Seiko is borne by craftsmen and women who have honed their craft to such an extent that they can adjust parts by hand to tolerances of one hundredth of a millimeter. This extremely detailed craftsmanship is what has made possible the very precise timekeeping delivered by the 9S mechanical movement.


Mechanical watches utilize an escapement, a self-contained device that draws its power from the motive force of a mainspring and uses the same power to regulate the speed at which the spring unwinds. It is a system which has remained largely unchanged since moving hands were first used to tell time.

As part of the mechanism, a wound-up mainspring exerts force to turn gears at a set speed as it unwinds. The precision of the system as a whole is dictated by this speed and the escapement mechanism, comprising the balance, pallet fork, and escape wheel.

The pallet fork sets the pace for the revolving escape wheel and it, itself, operates in accordance with the oscillating balance.

The balance rotates back and forth like a pendulum, ensuring that the mainspring unwinds at an even speed and over an extended period of time. In doing so, the balance effects the steady rotation of the hour, minute, and second hands.


Adjusting the hairspring – the key to precise timekeeping

The hairspring is the core component at the heart of a mechanical watch which governs its precision.

The elegantly coiled hairsprings are akin to living creatures, with an individuality all their own. Our craftsmen and women can identify and work with this variation, inserting pincers into the spaces within the coil to make adjustments by hand with a precision of one hundredth of a millimeter.

The beautiful ripple of a properly adjusted hairspring are enough to bring a smile to the face of any craftsman. To see the spring come alive is to witness the birth of a mechanical watch and the watchmaker’s work transcends manufacturing to become a work of art.


The balance wheel
– a pillar of precision

The balance wheel serves the important role of ensuring a consistent beat. The part is so critical to the overall precision of every Grand Seiko watch that its weight is adjusted to within tolerances of one ten thousandth of a gram.

Because it is so sensitive, even the slightest temperature change can cause it to expand or contract, potentially leading to distortions in shape.

The 9S mechanical movement minimizes effects of temperature on the balance wheel and preserves overall precision by adding a fourth arm over the usual two or three.

While this attention to detail increases the level of work required in the manufacture of components, Seiko is committed to preventing balance wheel deformation and maintaining ultimate precision.


Polished by hand

The power must flow between the gears with only minimal loss of energy to assure that the watch performs perfectly over time.

To ensure the efficient transfer of the critical power of the mainspring, Seiko’s craftsmen and women polish the grooves between the gear teeth one by one.

The painstaking but vital polishing of every gear tooth ensures that friction is minimized and that the longevity of every component is extended.


Quality control for the highest standard of accuracy

Precision beyond that of a chronometer

The first Grand Seiko, produced in 1960, was awarded official designation as a 'chronometer' according to the highest chronometer standard of the time. It carried the word ‘Chronometer’ on the dial.

Today’s Grand Seiko watches, however, no longer carry this designation because, in the 1970’s Grand Seiko introduced its own, higher, standard. The latest version of this standard, the New GS Standard, was established in 1998 and set standards more stringent than any other.

Some specially adjusted versions of Caliber 9S hold an even greater distinction. Designated with the ‘Grand Seiko Special Standard’, these versions have precision rates of +4/-2 seconds a day.

A 17-day trial

The 9S mechanical movement is assessed against a unique and rigorous set of standards over the course of 17 days. The movement is tested under various conditions including six different positions and three different temperatures, and its daily variations must fit within very strict tolerance rates in order to merit the status of Grand Seiko.

The pursuit of precision

Precision. It's the pursuit of every watchmaker. When Grand Seiko was born in 1960, it was ready to break tradition. After meeting the chronometer standards of the time, Grand Seiko set its own accuracy standards in 1966. By 1998, advancements in materials and craft gave rise to the New Grand Seiko Standard. Every movement undergoes rigorous testing in six positions and three temperatures over seventeen days. The craftsmen and women uphold their commitment to quality while consistently exploring the limits of possibility.

The Grand Seiko Standard



Grand Seiko Special Standard

Grand Seiko Standard

Grand Seiko Standard for women

Mean daily rate* in six positions

Second / day

-2.0 ~ +4.0

-3.0 ~ +5.0

-3.0 ~ +8.0

Mean variation of daily rate

Second / day

Less than 1.6

Less than 1.8

Less than 3.2

Maximum daily rate between two consecutive daily rates in the same position

Second / day

Less than 3.0

Less than 4.0

Less than 6.0

Variation of rate between positions horizontal and vertical

Second / day

-5.0 ~ +7.0

-6.0 ~ +8.0

-8.0 ~ +10.0

Maximum daily rate between mean daily rate and any individual rate

Second / day

Less than 7.0

Less than 8.0

Less than 13.0

Variation of daily rate per IC between 8℃ and 38℃

Second / day / ℃

-0.3 ~ +0.3

-0.5 ~ +0.5

-0.6 ~ +0.6

Variation of daily rate per IC between 23℃ and 38℃

Second / day / ℃

-0.3 ~ +0.3

-0.5 ~ +0.5

-0.6 ~ +0.6


Second / day

-4.0 ~ +4.0

-5.0 ~ +5.0

-6.0 ~ +6.0

Number of positions in inspection

6 positions

6 positions

6 positions

Condition of temperatures in inspection

8, 23, 38 ℃

8, 23, 38 ℃

8, 23, 38 ℃

Length of tests

17 days

17 days

17 days

Mean daily rate*: is a mean value of daily rates in a condition where the movement before assembly in a case is measured in 6 positions in a fixed manner under artificially controlled environment for 12 days.


Pursuing an ideal, since 1960.

From the very start, a precise perspective on time.

On December 18, 1960, the first Grand Seiko watch was unveiled. It expressed Grand Seiko’s commitment to the ultimate in precision, beauty and durability, ideals that still define Grand 

9S Mechanical movement


MovementMean daily rate*Normal usage accuracyPower reserveNumber of jewelsFeatures
Caliber 9SA5
(Automatic with manual winding)
+5 to -3 seconds per day +8 to -1 seconds per dayApproximately 80 hours47 jewels-Dual Impulse Escapement
-Twin barrels
-Instant date change mechanism
Caliber 9S86
(Automatic with manual winding)
+5 to -3 seconds per day +8 to -1 seconds per dayApproximately 55 hours37 jewels-Dual time function with 24-hour hand
-Quick correction function of time difference adjusting to a calendar
Caliber 9S85
(Automatic with manual winding)
+5 to -3 seconds per day +8 to -1 seconds per dayApproximately 55 hours37 jewels-Date display
Caliber 9S68
(Automatic with manual winding)
+5 to -3 seconds per day +10 to -1 seconds per dayApproximately 72 hours35 jewels-Date display
Caliber 9S66
(Automatic with manual winding)
+5 to -3 seconds per day +10 to -1 seconds per dayApproximately 72 hours35 jewels-Dual time function with 24-hour hand
-Quick correction function of time difference adjusting to a calendar
Caliber 9S65
(Automatic with manual winding)
+5 to -3 seconds per day+10 to -1 seconds per dayApproximately 72 hours35 jewels-Date display
Caliber 9S64
(Manual winding)
+5 to -3 seconds per day +10 to -1 seconds per dayApproximately 72 hours24 jewels
Caliber 9S63
(Manual winding)
+5 to -3 seconds per day +10 to -1 seconds per dayApproximately 72 hours33 jewels-Power reserve indicator
-Small seconds hand
Caliber 9S27
(Automatic with manual winding)
+8 to -3 seconds per day +10 to -5 seconds per dayApproximately 50 hours35 jewels-Date display
  • * This accuracy is the result of measuring the loss/gain of the time for seventeen days before the inside movements of the watch are put in the case. The measurement has been done in the factory where temperatures or position of the movements are controlled.

9S Mechanical models

MECHANICAL | Movement | About | Grand Seiko