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1. 5. 2022

A Super High Standard Shoulder to Shoulder With the World’s Best

Masayuki Hirota
Yoshifumi Takeda

Mechanical movements are powered by a mainspring. For a time, Seiko stopped making them for the Japanese market, but in the 1990s the company decided to revive the mechanical movement. It was in 1998 that the mechanism was restored to Grand Seiko.

Caliber 9S55 was the new self-winding movement developed for Grand Seiko. With its strong torque to turn the broad hands and its long power reserve of around 50 hours, this movement could meet the high precision requirements that Grand Seiko had set for itself. As one watchmaker later put it, after a long interval, Grand Seiko had suddenly furnished its watches with “a world-class self-winding movement.”

Caliber 9S65, the movement installed in SBGR051 released in 2010, is a completely revised version of the 9S55 movement. The power reserve was increased to 72 hours and, thanks to the use of a new material for the hair spring, the movement achieves twice the magnetic and shock resistance as that of its predecessor. The winding mechanism has also been improved, so that even when working at a desk, the mainspring can be wound with minimum arm movement.

In terms of durability, the knowledge from 9S8, the Mechanical Hi Beat released the previous year, has been incorporated throughout. All the mechanical parts are hardened to extend their longevity, while the escapement—the heart of the watch—has been fitted with an oil reservoir to prevent it from running out of oil. This means the 9S65 movement will retain oil for longer than the typical three years, while the parts will not wear out even if there is a shortage. In other words, it delivers high performance over the course of many years.

The exterior design of Grand Seiko is enough to attract many people, but it is the movement that makes this timepiece so highly regarded among watchmakers the world over.

At first glance, 9S65 looks unassuming, but it is a quintessential Grand Seiko. Despite being a standard movement, its performance stands shoulder to shoulder with the world’s best.


SBGR051 was launched in 2010. It is equipped with Caliber 9S65, a self-winding movement that represents the 9S mechanical movement. It is the worthy successor to 9S55, launched in 1998. The logo in SBGR051 has since been re-positioned and is now marketed as SBGR251.


Masayuki Hirota

Editor-in-chief of Chronos Japan edition and After graduating from university, he worked for an electronics manufacturer and an IT company. He started his carrier as a watch journalist from 2014. He has worked in his current position since 2017.



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