Grand Seiko T0 Constant-Force Tourbillon

The Grand Seiko T0 Constant-Force Tourbillon is a concept movement from the high-end Japanese watch brand. Apparently, its creation took place in parallel with the extraordinary Calibre 9SA5, released earlier this year. With its impressive specification, it appears to signify the brand’s desire to ascend into the rarefied world of haute horlogerie and, based on the last 60 years history, it will undoubtedly succeed.

Grand Seiko T0 Constant-Force Tourbillon

Founded in 1960, Grand Seiko has created numerous watches over the years, each proffering wearer comfort, excellent readability and outstanding precision. While the brand was initially the preserve of Japanese horophiles, improved availability led legions of watch enthusiasts dotted around the globe to enjoy the sweet taste of GS ownership.

The heady mix of gleaming dauphine-style hands, breathtaking dials and zaratsu polished cases proves an intoxicating cocktail, few aficionados can resist. Moreover, the brand employs MEMS technology (often termed LIGA in Europe) to create openworked escape wheels and pallet levers, thereby mitigating mass. The GS escape wheels incorporate small reservoirs in the tips of the teeth, holding onto lubricant for extended periods, mitigating friction, power consumption and wear. It is by employing this know-how that the company is able to offer its high-frequency 5Hz movements.

One benefit of a 5Hz movement (Swiss-lever escapement) is that it delivers superior precision when worn. Grand Seiko, along with some other Seiko brands, also offer Spring-Drive movements. These calibres are effectively a hybrid of mechanical and electronic power, bestowing a remarkable degree of precision, surpassing virtually all conventional mechanical movements. While Credor, the ultimate expression of Seiko ownership, makes hand-wound Spring Drive movements, Grand Seiko usually favours automatic calibres, delivering day-to-day wearer convenience.

Put simply, precision is an overriding obsession at Grand Seiko and sits at the fulcrum of the firm’s paradigm.

With increasing numbers of watch enthusiasts succumbing to the brand’s charms, it would be easy for the company to sit back and count its mountain of Yen, however, continuous improvement is part of the GS culture.

Earlier this year, as part of its 60th-anniversary celebrations, the brand unveiled its Calibre 9SA5. With the advent of this latest mechanical movement, the Japanese marque signalled it was aiming for the dizzying heights of haute horlogerie. The inventory of delights on the Calibre 9SA5 includes a dual impulse escapement, a variable-inertia balance, an overcoil, a supremely slender gear train and impressive finishing.

Now, the Marketing Communications Office in Tokyo has announced it has created a new movement, the Grand Seiko T0 Constant-Force Tourbillon. According to the Japanese company, this movement ‘inspired essential movement parts for the new Calibre 9SA5, which was developed in parallel with the concept creation’.

A ‘constant-force’ device ensures that the energy from the barrels, transmitted via the gear train and ultimately supplied to the escapement, remains consistent. On most watches, the power or torque is too great when the mainspring is fully tensioned and thereafter it diminishes. If the escapement receives the optimum amount of force, the balance’s amplitude will remain constant, thereby delivering superior precision. On a regular watch, when the force serving the balance diminishes, the amplitude drops, compromising accuracy.

Grand Seiko T0 Constant-Force Tourbillon

The tourbillon, originally patented by Abraham-Louis Breguet, is a means of countering the adverse influence of gravity on the regulating organ. Breguet came up with an idea of placing the escapement and regulating organ within a rotating cage, mitigating the adverse effects of gravity and thereby augmenting precision.

Unfortunately, the brand has not released too many details of its new concept at this stage and it has not specified if it will ever feature in a production watch, however, I hope it does. Where will Grand Seiko be in another 60 years? Based on past experience, I suspect it will be even bigger and better than today.

The brand’s press release

Ever since the first Grand Seiko was introduced in 1960, the pursuit for high accuracy has been fundamental in every Grand Seiko timepiece and innovation. Today, a new and exciting moment in its 60-year history is marked by the introduction of the brand’s first-ever concept creation.

The new creation is a masterwork and true revolution in watchmaking design and fully reveals the Grand Seiko designers’ capabilities and ingenuity. The T0 (T-zero) Constant-force Tourbillon incorporates a fully integrated constant-force mechanism and tourbillon on the same axis for the first time in the world. The constant-force mechanism provides even energy distribution to the escapement regardless of how much the mainspring is wound, and the tourbillon eliminates the error in precision caused by gravity by incorporating the escapement parts and balance in a rotating carriage. These two mechanisms alone require exceptional design and manufacturing technologies, and the integration of the mechanisms as one unit is a patented design that achieves a new level of accuracy for Grand Seiko’s mechanical watchmaking.

In pursuit of the highest level of accuracy for mechanical watchmaking, the designers conceptualized the new creation without restrictions from production capability considerations. The free approach to development resulted in the birth of T0 and inspired essential movement parts for the new Caliber 9SA5, which was developed in parallel with the concept creation.

T0 is displayed on the second-floor lounge of the Grand Seiko Studio Shizukuishi inaugurated on July 20, 2020, in Shizukuishi, Morioka. The rotating tourbillon and intermittent turning of the constant-force, as well as the rhythmical 16th note ticking sound of the mechanisms, can be thoroughly enjoyed.

As soon as the Coronavirus situation allows, the new studio looks forward to welcoming visitors. For information and reservations, please visit the site below.

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