Grand Seiko 60th Anniversary Limited Edition SLGH002

The Grand Seiko 60th Anniversary Limited Edition SLGH002 features a new ‘Hi-beat’ movement, the Calibre 9SA5. When contrasted with the brand’s existing Calibre 9S85, this new movement is slimmer, more precise and runs autonomously for longer. Angus Davies takes a close look at this new watch, paying particular attention to its new movement.

Grand Seiko 60th Anniversary Limited Edition SLGH002

In the world of manufacturing, certain words and phrases are part of the vernacular so beloved by management types. For example, ‘Kanban’ is a scheduling system created for improving manufacturing efficiency, conceived by an engineer working at Toyota. Likewise, the term ‘5S’ describes an organisation system, developed in Japan, which pays close attention to the tidiness of the workplace, ensuring the ideal environment for ‘Just in Time’ manufacturing.

However, perhaps the best known term, familiar to legions of middle managers, is ‘Kaizen’, meaning ‘change for the better’. It embodies a key aspect of Japanese culture, namely, to collectively harness the talents within a company in order to facilitate continuous improvement. This philosophy appears to be alive and well at Grand Seiko.

The Calibre 9S85

Few companies make 5Hz movements as they present a number of technical challenges. High-frequency movements have a tendency to quaff lubricants, the escapement is more prone to wear and the power-reserve is often shorter. Only a handful of companies have overcome these challenges and successfully produced a 5Hz movement. Grand Seiko is one such firm, producing vast numbers of its Calibre 9S85 since it was first released in 2009.

With a high-frequency calibre, the balance is less susceptible to shocks and the movement is less prone to positional errors when worn.

The Calibre 9S85 employs MEMS (Micro Electrical Mechanical System) technology (usually termed Lithographie, Galvanoformung, Abformung (LIGA) in Europe). The use of this technology facilitates the making of small components to infinitesimal tolerances. The pallet lever and escape wheel are openworked, reducing mass and thereby mitigating energy consumption. In addition, the surfaces of each component exhibit an extraordinary smoothness, ameliorating friction and, once again, mitigating energy consumption. The intricately-formed teeth found on the escape wheel feature small reservoirs that hold on to lubricants for longer, attenuating wear.

While the power reserve of the Calibre 9S85 does not match that of the Calibre 9S65, an automatic 4Hz movement, it can still run autonomously for up to 55 hours, a respectable figure by any measure. 

Continuous improvement

As stated earlier, the Calibre 9S85 was unveiled in 2009 and still features in several Grand Seiko watches, including some I would dearly love to own. Indeed, its incredible reliability is known to many watch collectors.

Unusually for the watch industry, this calibre has not received any facelifts over the years. However, I am reminded of the saying, ‘if it ain’t broke don’t fix it’. Nevertheless, with the word ‘Kaizen’ ringing in its ears, Grand Seiko has just unveiled a new 5Hz movement, the Calibre 9SA5. The arrival of this new movement coincides with the 60th anniversary of Grand Seiko’s inaugural watch.


Grand Seiko 60th Anniversary Limited Edition SLGH002

The high-end watch brand has chosen to house its new high-frequency movement within the new Grand Seiko 60th Anniversary Limited Edition SLGH002.

The specification sheet for the Calibre 9SA5 reveals a multitude of enhancements, immediately justifying the rationale for change.

The dial

Devotees of the Japanese brand will immediately feel at ease with the appearance of the new Grand Seiko 60th Anniversary Limited Edition SLGH002. The silver-toned dial features a sunray motif and the company’s logo is positioned just below noon.

Grand Seiko 60th Anniversary Limited Edition SLGH002

Consistent with several other Grand Seiko watches, the new timepiece is endowed with dauphine-style hour and minute hands which are facetted, upholding GS tradition. Closer inspection reveals that they also have truncated tips and counterweights.

The indexes, GS logo and ‘calendar frame’ are formed of 18-carat yellow gold. The indexes feature a channel and numerous facets. Grand Seiko’s predilection for facetted surfaces, visible on both the hands and indexes, surpasses mere aesthetics. Each angled surface ensnares available light, heightening legibility.

Grand Seiko 60th Anniversary Limited Edition SLGH002

The white date disc features black numerals which slightly vary in shape and size, again augmenting readability. In addition, the date change is ‘virtually instantaneous’. A slender central sweep seconds hand spans the dial, kissing a minuterie which is presented on a rehaut adjacent the dial. The Grand Seiko 60th Anniversary Limited Edition SLGH002, consistent with all models from the brand, succinctly imparts the time.

The case

I freely admit to being a ‘Grand Seiko geek’. One of the extraordinary aspects of Grand Seiko, and there are many, is the case execution. All contours and edges are wonderfully defined. Both the steel and titanium cases are imbued with a silky-smoothness, courtesy of the firm’s legendary zaratsu polishing. Grand Seiko does not specify whether the 18-carat yellow gold case of the 60th Anniversary Limited Edition SLGH002 has been polished using the same technique, however, rest assured it remains a paragon of refinement.

Grand Seiko 60th Anniversary Limited Edition SLGH002

The case tastefully blends polished and straight brushed surfaces. Placing two contrasting finishes in close proximity proves very challenging, requiring an onerous blend of skill and time. Needless to say, one glance at the case of this watch demonstrates that Grand Seiko is clearly up to the task. Indeed, the interplay between both types of finish endows the case with a tasteful mien. When viewing the Grand Seiko 60th Anniversary Limited Edition SLGH002 from the side, the arcing case band comes into view. Its shape seems ergonomically predisposed to snuggle the wrist.

The upper sapphire crystal is box-shaped, further heightening the classical character of the watch. However, unlike a vintage or classical watch, the 60th Anniversary Limited Edition SLGH002 features an exhibition case back, affording views of the self-winding movement within.

Movement – an introduction

As previously stated, the Calibre 9S85 was, and still remains, an exceptional movement. Now, with the advent of the Calibre 9SA5, the Japanese luxury brand has raised the bar to another level. Indeed, the new movement’s various attributes are seldom seen at this price point and are sometimes lacking on watches with six-figure pricing.


The new 5Hz movement fitted to the Grand Seiko 60th Anniversary Limited Edition SLGH002, the Calibre 9SA5, is slimmer and proffers a longer power-reserve, delivering 80 hours of autonomous operation when fully wound. These two improvements should be mutually exclusive, but somehow Grand Seiko has delivered horological advancement in both areas.

Dual impulse escapement

Most mechanical watches are equipped with a Swiss lever escapement which sends an impulse indirectly to the balance via a pallet lever. The inherent problem with this arrangement is that the transfer of energy is not 100% efficient and power is lost.

The dual impulse escapement still uses an indirect impulse, similar to a conventional Swiss lever escapement, when the balance wheel rotates in one direction. However, a further pallet, affixed to the balance, engages with the escape wheel directly, receiving a direct impulse when the balance wheel rotates in the opposite direction. This approach mitigates energy consumption and, by default, increases the power-reserve.



Similar to the escape wheel and pallet lever used within the Calibre 9S85, the corresponding parts within the Calibre 9SA5 are formed using MEMS technology. Again, they are openworked, mitigating mass, supremely smooth, reducing friction, and feature an elaborate design. Collectively, these attributes also contribute to the movement’s impressive 80 hour power reserve.

Free-sprung balance and overcoil

Most mechanical movements, including the Calibre 9S85, feature an index-adjuster. The hairspring is affixed to the balance cock with a ‘stud’ and passes between two ‘curb pins’ fitted to a ‘raquette’. If the raquette is moved towards or away from the ‘stud’, the effective length of the hairspring changes, becoming longer or shorter, thereby influencing the rate of the movement.

A potential problem with this approach is that the position of the hairspring relative to each curb pin can influence the rate. In particular, a shock can lead to the hairspring moving between the curb pins, causing the effective length of the hairspring to alter and, thereby, changing the rate of the movement.

The Calibre 9SA5 is fitted with a free-sprung balance, which is technically superior. The length of the hairspring is fixed and the rate is adjusted using timing screws or weights (masellotes) to influence the balance’s moment of inertia. Although it is more labour intensive to set-up than an index-adjusted balance, it allows finer adjustment, hence offering greater precision.

Another benefit of a free-sprung balance is that the hairspring has a tendency to ‘breathe’ more concentrically while the balance wheel oscillates to and fro. This is termed ‘isochronism’ and again has a positive influence on precision. Also, a free-sprung balance is less susceptible to positional influence. Lastly, as the length of the hairspring is fixed, the precision of the movement is less susceptible to change over an extended period.

Grand Seiko has clearly obsessed over the smallest details, indulging the desires of all self-respecting horophiles. For example, the four timing screws fitted to the balance wheel are positioned ‘in-board’, set within recessed sections of the balance wheel rim. As the balance wheel oscillates, the screws create less air turbulence which, in turn, aids precision.

The term ‘Breguet overcoil’ is part of horological parlance. This system involves ‘raising’ the outer coil of the hairspring and imbuing it with a curve to a predetermined shape. This enhancement, necessitates more time and expense, however, it improves isochronism. Grand Seiko has, once again, sought its own path to greatness, referring to its ‘overcoil’, making no reference to the famous Swiss watchmaker. The curved shape of its overcoil was chosen ‘after more than 80,000 simulations with the result that its performance is optimised in every possible position’. Indeed, this illustrates a further benefit of an overcoil, namely it is less susceptible to positional influence.

Horizontal gear train

Grand Seiko state the Calibre 9SA5 is ‘15% slimmer than the current Grand Seiko high beat caliber’. The constituent parts of the gear train have been arranged in such a way as to decrease the overall thickness of the movement. In addition, the gear train is positioned at the same height as the twin barrels, again providing the movement with a svelte torso.

Movement – design and finishing

The Calibre 9SA5 is endowed with unusual curved bridges, said to be inspired by the ‘shapes of Mt. Iwate and a bend in the Shizukuishi River that runs near to the studio where the watch is made’. Certainly, the design of the bridges proves very attractive. Furthermore, the balance bridge is affixed at two points conferring improved stability.


An openworked oscillating mass harnesses the motion of the wearer’s wrist to energise the two mainsprings. The openwork design of the oscillating mass affords sight of various movement components usually hidden from view. The edge of the oscillating weight runs in a channel (trottoir) encircling the movement.

The bridges are embellished with a striped pattern, similar to Côtes de Genève motif, and feature golden engraved text. Perlage adorns the main plate and there is a plethora of blued screws. Most notably, the finishing looks less ‘industrial’ than previous Grand Seiko models and more befitting of this horological tour de force.

Movement – additional comments

On several occasions I have been engaged as a public speaker, talking about my favourite topic, watches. At such events, I am frequently asked about power-reserves and, in particular, increasing the time a watch will run autonomously. There is an assumption that a longer mainspring and larger barrel allows a movement to run unattended for lengthy periods. Sadly, it is not as simple as this.

When a mainspring is tensioned it will send power to the escapement which duly sends an impulse to the balance. The balance wheel oscillates to and fro. The swing of the balance or angle of rotation is described as the ‘amplitude’, expressed in degrees (°). Ideally the amplitude should typically be 270° – 315°. Excessive amplitude can lead to ‘knocking’, while insufficient amplitude can compromise precision. Put simply, a huge mainspring is generally undesirable.


Grand Seiko has equipped the Calibre 9SA5 with two barrels, arranged in sequence (parallel). This ensures the power transmitted to the escapement is more consistent, providing a positive influence on the amplitude and precision. Incidentally, some brands arrange two barrels in series, one above the other. In this instance, Grand Seiko has placed the barrels side by side, mitigating the thickness of the movement.

Throughout this article, I have referred to ‘accuracy’ or ‘precision’ and detailed many features on the Calibre 9SA5 which contribute to the performance of the watch. While the stated accuracy of this movement is +5 to -3 seconds per day, the same as the Calibre 9S85 (5Hz) and the Calibre 9S65 (4Hz), these stated figures are all based on static conditions. When the watch is worn in a variety of positions (dynamic), the superior precision of the Calibre 9SA5 will be manifest.

Closing remarks

While the exterior of the Grand Seiko 60th Anniversary Limited Edition SLGH002 appears classical, bearing a resemblance to the company’s iconic 44GS of 1967, the movement brims with modernity and innovation.

The dial of the SLGH002 is highly legible, rich in detail and blessed with a prepossessing appearance. Furthermore, the 40mm case, with its slender profile, should suit an array of wrists. Juxtaposing contrasting case finishes, while keeping each surface discrete, is a huge undertaking requiring both skill and time. Evidently, Grand Seiko has both of these resources in abundance, executing the case finish with notable aplomb.

Despite the array of attributes making the SLGH002 worthy of consideration, it is somewhat overshadowed by the brilliance of its movement, the new Calibre 9SA5. Usually, when I write about the movement within a watch, a few paragraphs suffice. However, when it came to writing about this latest ‘Hi-beat’ calibre, listing its many specification details and relaying the benefits they provide, a few paragraphs did not seem to cut it.

Grand Seiko 60th Anniversary Limited Edition SLGH002

While I admire the Grand Seiko 60th Anniversary Limited Edition SLGH002, its undoubted excellence is beyond my financial grasp, however, last month, Shinji Hattori, Chairman & CEO of the company provided me with some hope. He stated the ‘Caliber 9SA5 is an entirely new movement and the foundation upon which a whole new generation of Grand Seiko mechanical watches will be created’. These words have piqued my interest, perhaps suggesting more accessible steel and titanium options may be around the corner.

The Caliber 9SA5 has collectively harnessed the company’s talents and delivered tangible progress. Clearly, Grand Seiko understand the meaning of ‘Kaizen’ and I, like many fans of the brand, look forward to witnessing its penchant for continuous improvement, again and again.

Further reading

Technical specifications

  • Model: Grand Seiko 60th Anniversary Limited Edition SLGH002
  • Case: 18-carat yellow gold case; diameter 40mm; height 11.7mm; water resistance 10ATM (100 metres); box-shaped sapphire crystal to front; sapphire caseback.
  • Functions: hours; minutes; central sweep seconds; date
  • Movement: Caliber 9SA5; Self-winding movement; frequency 36,000 vph (5Hz); 47 jewels; power reserve 80 hours.
  • Strap: Brown crocodile leather strap paired with a 18-carat yellow gold 3-fold clasp with push button release.
  • Price: £38,600 including VAT (RRP as at 23.4.2020)
  • Limited Edition: 100 pieces

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