Grand Seiko's precision rivals that of Swiss watches. Introducing its unique standards and technologies

Founded in 1960, Grand Seiko is a world-renowned luxury watch brand from Japan. Grand Seiko watches, crafted with unparalleled attention to detail, are comparable to Swiss watches. Let's take a look at Grand Seiko's precision, technology, and standards.

What is the accuracy of a watch?

The accuracy of a clock can be summed up in one word: "accuracy of time." During the Age of Discovery, when Europeans began setting sail in the 15th century, measuring the position of the sun and the exact time was essential in order to determine accurate latitude and longitude in England.

The marine chronometer was developed for this purpose, and as time passed, the level of precision required of watches became ever higher.

So how is the accuracy of a watch judged today? Let's take a look at some of the major standards.

Proof of high precision: COSC certified

COSC (The Contrôle Officiel Suisse des Chronomètre) is the Swiss Official Chronometer Testing Institute. It certifies high-precision movements that pass rigorous testing, and has played an important role in the Swiss watch industry since its establishment in 1973.

Once a movement is sent to the COSC testing center, it immediately undergoes rigorous testing, including mean daily rate of change, mean daily temperature difference, maximum daily temperature difference, difference between vertical and horizontal positions, maximum positional deviation, change in values ​​due to temperature changes, and change in values ​​when the movement is stopped and then restarted. Only movements that pass the required criteria are issued a certification.

In recent years, over 160 million watches have passed COSC inspection annually. However, this only accounts for around 6% of all watches exported from Switzerland, of which only around 21% are mechanical watches, demonstrating the strictness of the inspection standards.

Other standards such as the Hallmark of Geneva

The Geneva Hallmark is a movement standard established by the Canton of Geneva, Switzerland, and is inspected in Geneva. It is applicable to movements for which the applicant company has its headquarters in the Canton of Geneva and all component manufacturing and assembly work is carried out within the Canton of Geneva.

In the past, regulations mainly focused on the decoration and finishing of the movement and the materials used, but in recent years, the focus has shifted to practicality and quality, such as water resistance and power reserve. Once certified, the watch will be stamped with the coat of arms of the city and canton of Geneva.

Other certification bodies include the Fleurier Qualité, run by the Swiss Foundation for Quality, and the Besançon Observatory, the only testing body in France. High-precision watches that have undergone rigorous inspections by these bodies will likely continue to be released into the world.

Grand Seiko Standards

The precision of movements is rigorously inspected by the certification bodies mentioned above. So how are Grand Seiko watches inspected? We will explain the precision standards for Grand Seiko movements.

The new GS standard is stricter than the chronometer standard.

The chronometer standard is the COSC standard. In 1998, Grand Seiko established the "New GS Standard," which exceeds this standard in accuracy.

The strict standards require the watch to be tested for an average daily rate of +5 to -3 seconds over 17 days in six positions and at three different temperatures. This uncompromising commitment to precision is one of the attractions of Grand Seiko.

GSS standard is even stricter than the new GS standard

Furthermore, Grand Seiko has established the Grand Seiko Special (GSS) standard, which is even stricter than the new GS standard.

The inspection is even stricter, with a static accuracy of +4 to -2 seconds per day, a level that can only be achieved by skilled craftsmen who spend many times more time and effort than with a regular mechanical watch, and only a small number can be produced per year.

The Caliber 9S 20th Anniversary Limited Edition model, which passed the GSS standard inspection, was sold in only 150 pieces worldwide.

The word "SPECIAL" is inscribed on the dial of watches that pass the GSS standard inspection, which is proof that they are equipped with a special movement.

The technology behind Grand Seiko's precision

The precision of Grand Seiko luxury watches is supported by the technology that Grand Seiko has honed over the years. The 9S Mechanical movement in particular incorporates an abundance of cutting-edge technology and the skills of its artisans.

Let us introduce the various technologies that support Grand Seiko's precision.

High-precision parts manufacturing using cutting-edge technology

Grand Seiko incorporates a variety of cutting-edge technologies, particularly in the 9S Mechanical, which uses the cutting-edge technology "MEMS (Micro Electro Mechanical Systems)" to manufacture the escapement parts.

MEMS is a technology that applies semiconductor manufacturing techniques and makes it possible to create lightweight parts with extremely small precision, down to 0.001mm. This makes it possible to produce small parts with even greater precision, such as the escape wheel, which has been molded to be 5% lighter, and the pallet fork, which has been 25% lighter.

Adjusting the balance spring

The balance spring is one of the components that make up the balance wheel, and is the most important heart of a mechanical watch, determining its accuracy. Just like a living thing, each balance spring has its own unique personality.

Grand Seiko's craftsmen create the heart of the 9S mechanical watch by repeatedly adjusting the balance spring to a precision of 1/100mm, relying only on the sense of touch to suit the unique characteristics of each hairspring.

Adding more support pillars for the balance wheel

The balance wheel is responsible for adjusting and controlling the reciprocating motion of the pallet. It is such an important part that affects the accuracy of a watch that its weight is adjusted to within 0.000001g to stabilize its rotation.

It is a very delicate part, and even slight changes in the environment can cause it to expand or contract, which can affect the accuracy of the watch. Therefore, in the 9S Mechanical, the balance wheel has four supports instead of the usual two or three, reducing the impact of environmental changes.

It is this meticulous attention to detail that supports Grand Seiko's meticulous precision.

Focusing on accuracy changes the way you look at watches

When looking at a watch, we tend to focus on the visible parts such as the design and functions, but it is the internal mechanisms that are packed with technology and attention to detail in watches.

"Keeping time accurate" is one of the most basic requirements for a watch, yet it is also the most difficult to achieve. Grand Seiko's standards surpass even those of COSC. By focusing on precision, perhaps your perspective on Grand Seiko watches will change.