We have once again received rare models from the past from Grand Seiko, which is currently holding a large-scale fair event at our store. The SBGA403 was announced in 2019 to celebrate the 20th anniversary of Grand Seiko's flagship movement, Spring Drive .

Continuing from the last time, we will introduce this model that fans must see again.

Model number: SBGA403

Case diameter: 44.5mm

Drive system: Equipped with Spring Drive 9R15

Waterproof performance: 20 ATM water resistant

Price: ¥1,265,000-(tax included)

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I think everyone has heard the name of the movement Spring Drive, but I feel that it is quite difficult to grasp the actual structure. This is because, as you can see on any website, it is written that it is a hybrid of quartz and mechanical watches , and when trying to deepen your understanding of Spring Drive, you should consider the structure of both mechanical and quartz watches. Isn't it because it's a premise to understand it? However, I also feel that this expression "hybrid" is the most eloquent word for understanding Spring Drive.



That said, it would be nonsensical to write about the structure of a mechanical watch, a quartz watch, and even a Spring Drive in one blog, so I will explain the Spring Drive in as easy-to-understand terms as possible.

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<Background of Spring Drive>

Why was Spring Drive created in the first place? In the previous article, I focused on Seiko's development of the world's first quartz watch in 1969, but in the latter half of the 1970s, the movement to quartz began to advance rapidly throughout the watch industry. At a time when the world was flooded with quartz watches, there was a young engineer at Suwa Seikosha (now Seiko Epson) who envisioned a watch with a completely new mechanism.



Joined Suwa Seikosha in 1971 and was involved in the development of quartz watch batteries and the "Twin Quartz" equipped with a crystal oscillator that compensates for errors caused by temperature changes in addition to a normal crystal oscillator. His name is Yoshikazu Akabane .

Source: https://museum.seiko.co.jp/seiko_history/milestone/7f09daa36ee9bdeb7bacacd0eb26654ed1641799/

Mr. Akahane, who succeeded in dramatically improving the accuracy of watches through the development of twin quartz, applied the method of correcting the accuracy of the twin quartz and came up with the idea of ​​``a quartz lock that corrects a mechanical watch using a quartz standard.'' I will apply for a basic patent in 1978.

Akahane explains the principle of the quartz lock as follows: ``For example, if you were to ride a bicycle down from the top of a mountain guided by an accurate pacemaker, the energy required for the bicycle to descend would be enough. Just apply the brakes well.” The basic structure of today's Spring Drive was created by comparing the pacemaker to the principle of a regular, high-precision quartz watch, and the dismounting bicycle to the structure of a mechanical watch.

If we apply this to the drawing of the spring drive that we often see,

(1) Like a mechanical watch, the force is transmitted to the gears by the repulsive force of the mainspring that is wound up and unwound.

(2) When part of the force is transmitted to the rotor, which uses magnets, it rotates, causing a change in magnetic flux and generating "electricity."

(3) The generated electricity passes through the IC and causes a part called a crystal oscillator to vibrate at high speed. (32768 times per second)

(4) In the circuit on the way, the high vibration of 32768 times is converted into a signal of 8 times per second (8Hz), which is suitable as a signal for a mechanical watch.

⑤Finally, by limiting the rotation of the rotor that is too fast or too slow with the IC to the reference signal of 8Hz, it becomes a mechanical yet ultra-precise spring drive.



I explained it quite briefly, but there were many problems before the Spring Drive was completed, the development was discontinued twice, and there were many dramas such as the obituary of Mr. Akabane, the creator. We will talk about this on another occasion.

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The SBGA403 was released to commemorate the 20th anniversary of the birth of Grand Seiko's flagship movement.

The new case design, which has never existed before, is made with the image of a lion, which has been a symbol of dignity and king since ancient times and is also a symbol of the brand. Doing.



It looks voluminous and feels heavy, but the case and bracelet made of bright titanium are surprisingly light and refreshing to wear.



The dial with a novel design that attracts what you see expresses "a young lion's mane".

The texture of the fur is beautifully applied by the hands of craftsmen, and the sweeping second hand unique to Spring Drive ticks the time elegantly on the mane, which is said to symbolize the strength and bravery of a lion.



The movement "9R15" equipped with this watch has been specially adjusted for accuracy, achieving high accuracy of up to ±0.5 seconds, compared to the normal daily difference of ±1 second. As a proof that it is equipped with a specially adjusted movement, the oscillating weight that can be seen from the back cover of the see-through back has a shining 18K yellow gold lion emblem.



What did you think. It is a genuine last chance for those who were looking for it because it is a rare model from the past. Please contact us as soon as possible if you are interested in the fact that only one is available here.

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<Event announcement>

<Grand Seiko Collection 2021, Japan's largest Grand Seiko event>

Japan's largest Grand Seiko event "Grand Seiko Collection 2021" will be held at the Eye Isuzu flagship store on March 20th (Sat) and 21st (Sun). At this event, which celebrates Seiko's 140th anniversary, we will offer a full lineup including new models for 2021 and past limited models. We have prepared wonderful novelties for visitors and customers who have signed contracts, so we will offer you the highest level of performance and sophisticated design that only a few true manufactures in the world can achieve. I hope you will take a look.



In order to prevent the spread of the new coronavirus, we recommend that you make a reservation. In order to avoid the three Cs, if the number of people exceeds the capacity of 40 people, admission may be restricted, but if you make a reservation, you can enter without waiting. You can proceed to the "visit reservation page" from the above page, so we appreciate your cooperation in making an advance reservation.





Ai Isuzu Yamaguchi