A Look Inside Grand Seiko’s 9S Mechanical Movement

Grand Seiko is no stranger to high-grade, high-accuracy mechanical movements, and today’s Grand Seiko calibers are built on the brand’s storied heritage of mechanical excellence. Through an expert combination of traditional watchmaking and state-of-the-art manufacturing, Grand Seiko is able to make movements that are hard-wearing, reliable, accurate, and superbly finished.

First and foremost, it should be noted that Grand Seiko is a fully-integrated manufacture — they produce all components in-house. Located in Morioka, Japan, Grand Seiko’s Shizukuishi Watch Studio is where Grand Seiko’s mechanical watches are made from start to finish, beginning with the manufacture of individual components, and ending with casing, testing, and final inspection.

When I visited Japan, I had the good fortune of seeing Grand Seiko’s manufacturing facilities up close. They were highly impressive, and it was truly one of the more interesting manufactures I’ve experienced. I witnessed parts both big and small get machine-cut, and then I watched those parts get hand-finished by Grand Seiko artisans.

Final assembly of the movements is a highly controlled process, and Grand Seiko entrusts about 20 watchmakers who are capable of adjusting the balance by hand. For the hairspring, specialized craftsmen and women work within tolerances of .01mm. This strict attention to detail ensures the brand’s incredibly strident standards. In the case of their standard mechanical movements, Grand Seiko boasts an exacting + 5/- 3 seconds-a-day standard, which surpasses the standard put forth by the COSC.

Additionally, Grand Seiko movements go through a comprehensive 17-day testing process, and the watches are tested in six positions versus the COSC’s five. Grand Seiko also has very stringent temperature tests where they test the same three temperatures as COSC, but then perform a secondary test on the hot and cold temperatures, something not done by the COSC.

Grand Seiko’s 9S mechanical movements boast an exacting + 5/- 3 seconds-a-day standard, which surpasses the standard put forth by the COSC.

Grand Seiko is known for some pioneering manufacturing processes; chief among them is MEMS. MEMS stands for Micro Electro Mechanical Systems, and it allows Grand Seiko to produce micro components that are lighter, more precise, and more durable than those same components produced through traditional machine cutting. Grand Seiko makes their pallet forks and escape wheels through MEMS.

Spron is the name of Grand Seiko’s proprietary alloy used to make their mainsprings and hairsprings. This alloy has evolved over the years, with each subsequent version improving on overall elasticity and resistance against heat and corrosion. One of the most interesting tests I got to see was when a watchmaker manipulated and stretched a Spron hairspring a good three inches, and then it was returned to its original form with no warping or damage in sight. Such manipulation isn’t possible with many metallic hairsprings, and it would surely snap a silicon hairspring in half.

Performance aside, Grand Seiko’s 9S mechanical movements are beautiful to look at. They’re finished to an incredibly high standard, and feature a host of high-end finishes that give the whole thing a luxurious look and feel. And it’s this mix that draws many to Grand Seiko. The combination of high-performance and elegant finishing, all made possible through a clever formula that mixes machine processes and human craft, really raises Grand Seiko above the competition.

To read other installments in this series, click here. To explore Grand Seiko’s 9s mechanical range, visit Grand Seiko.

The movements and watches featured here are instructional samples. No Grand Seiko watches or movements were hurt in the making of this series.