Grand Seiko Introduces a New Hi-Beat Caliber with an Extended Power Reserve, Housed in a Limited Solid Gold Dress Watch

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Grand Seiko continues their year long celebration of the brand’s 60th anniversary this week with the release of several new watches and a few new calibers that should have enthusiasts and fans of the brand particularly excited. We’ll get to all of the new stuff, but we’re starting with perhaps the most significant technical innovation that Grand Seiko has introduced in years, the new hi-beat caliber 9SA5. The new movement is featured in a stunning and classically styled gold watch, and contains a bunch of new features and tech that brings hi-beat watchmaking to exciting new levels. Let’s jump right in.


Grand Seiko SLGH002

  • Case Material: Yellow gold
  • Dial: Silver
  • Dimensions: 40 x 11.7mm
  • Crystal: Sapphire     
  • Water Resistance: 10 bar
  • Crown: Push/pull              
  • Movement: 9SA5
  • Strap/bracelet: Crocodile strap
  • Price: $43,000 
  • Reference Number: SLGH002
  • Expected Release: August 

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Grand Seiko have been pioneers in the crafting of high frequency movements from the beginning. These calibers take great skill and ingenuity to create, with a need to balance the increased levels of pure power that they deliver operating at a higher frequency (Grand Seiko hi-beat movements run at 36,000 vph) with overall movement size. There are always compromises that need to be made, which is why high frequency movements tend to not have incredibly long power reserves. Grand Seiko, with this new movement, set out to create a caliber that operates at their high beat rate, with Grand Seiko’s trademark accuracy, for up to 80 hours. 

Spoiler alert: they succeeded. But it took advancements on three key levels. First, the escapement is all new. Grand Seiko’s Dual Impulse Escapement is an all new in-house design, and a major advancement in watchmaking. Whereas a traditional lever escapement impulses the balance wheel indirectly once with every turn, Grand Seiko’s innovation here is to impulse the balance twice while using the same amount of energy. Efficiency is increased by the escape wheel transmitting power directly to the balance when swinging in one direction, and through a traditional pallet fork when swinging in the opposite direction. Energy from the escape wheel essentially hits the balance wheel directly and indirectly, borrowing from traditional Swiss lever escapement functionality, but expanding on it greatly. 

Increased power reserve in the new movement comes from Grand Seiko’s ability to fit a second mainspring barrel into the movement, and reducing the weight of the escapement significantly when compared to the current 9S85 movement. This efficiency is accomplished largely through their use of MEMS technology. (For more on MEMS, check out this deep dive into Grand Seiko’s current stable of hi-beat movements).

The new Dual Impulse Escapement impulses the balance directly and indirectly for maximum efficiency.
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A new escapement is a big deal, but it doesn’t tell the whole story of the 9SA5. The new caliber also features an all new free sprung balance, developed specifically for this movement. This is the regulating organ of the watch, and the overcoil hairspring used here is new for Grand Seiko, which has traditionally incorporated flat hairsprings in their balance assemblies. The advantage of the overcoil hairspring is primarily in its ability to retain its precision for longer periods of time, and to resist shock and friction. The trade-off is in the manufacturing and initial regulating process – it takes extremely skilled craftspeople many years to learn how to properly regulate a balance made in this fashion. 

The new free sprung balance is the regulating organ of the movement.

Finally, Grand Seiko has made adjustments to the layout of the gear train in the 9SA5 caliber. The mainspring barrel and gear train are now arranged horizontally, resulting in a movement that is 15% thinner than the current version of Grand Seiko’s 9S caliber. This addresses a common critique of Grand Seiko’s watches, that while they’re technically built to an incredibly high standard, and finished to the nines, they remain too thick for many watch lovers.

The first watch to house the new 9SA5 movement is the solid gold SLGH002. Made in a run of just 100 pieces to celebrate the 60th anniversary of the brand, the SLGH002 is a traditional dress watch with a case based on the iconic 44GS style of the late 60s. At 40mm and just under 12mm thick, the SLGH002 takes advantage of the thin new movement inside of it with a design that is meant to hug the wrist. If you enjoy old school Grand Seiko design, this watch will have a lot of appeal – it’s clean and crisp, and of course features the immaculately finished hands and hour markers (again, in solid gold) that we expect from Grand Seiko, at any price point. 

At $43,000, this SLGH002 is obviously not a watch for the masses. But the new generation hi-beat movement, one would hope, will eventually trickle down into more mass market friendly designs. Until then, we’ll be happy to admire the SLGH002 from afar. Grand Seiko

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Zach is a native of New Hampshire, and he has been interested in watches since the age of 13, when he walked into Macy’s and bought a gaudy, quartz, two-tone Citizen chronograph with his hard earned Bar Mitzvah money. It was lost in a move years ago, but he continues to hunt for a similar piece on eBay. Zach loves a wide variety of watches, but leans toward classic designs and proportions that have stood the test of time. He is currently obsessed with Grand Seiko.
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