|Manufacturer||Grand Seiko (Seiko Watch Corporation)|
|Movement Type||Automatic, self-winding mechanical, chronograph|
||36,000 vph (10 beats/sec)|
|Functions||Central hours; central minutes; central chronograph stopwatch seconds; small running seconds subdial at 3:00 (60 seconds); 30 minutes chronograph counter at 9:00; 12 hour chronograph counter at 6:00; date at 4:30|
||Dual Impulse Escapement, twin barrels, instant date change (Date Finger mechanism)|
|Country of Manufacture||Japan|
||Grand Seiko Tentagraph (Ref: SLGC001)|
The Grand Seiko caliber 9SC5 (9SC5A) is a hi-beat automatic chronograph watch movement. This caliber is found in the Grand Seiko Tentagraph chronograph which was introduced at Watches and Wonders 2023 on March 27, 2023 (available for purchase in June 2023). Building upon the 9S family of mechanical movements, the 9SC5 is the first mechanical chronograph caliber ever produced by Grand Seiko.
In Grand Seiko’s own words:
“The pursuit of precision is at the heart of the Grand Seiko Tentagraph, which features the new Caliber 9SC5. This Hi-Beat chronograph movement beats ten times per second, ensuring high accuracy when measuring the time of day as well as elapsed time. With its energy-efficient architecture, the movement runs for three days even with the chronograph function in operation. 9SC5 introduces a new testing procedure, which now includes an extra three days to assess the watch in three positions while the chronograph is running.” –Source
Some of the topics covered in this caliber listing:
Grand Seiko Tentagraph:
“In 2023, Grand Seiko’s first mechanical chronograph, the Tentagraph, was born. The Tentagraph’s name describes the characteristics of the Caliber 9SC5 that powers this watch: “TEN beats per second”, “Three days of power reserve”, “Automatic,” and “chronoGRAPH. A high-beat chronograph that symbolizes the next generation of Grand Seiko watchmaking, the Tentagraph Caliber 9SC5 has 72 hours of power reserve (approximately 3 days) even when the chronograph function is in operation, making it the ten-beat chronograph with the longest power reserve in the industry today.”-Source
9SC5 Column Wheel and Vertical Clutch:
In Seiko’s own words:
“Caliber 9SC5 features both a vertical clutch and a column wheel, two hallmarks of a high-quality modern chronograph. The vertical clutch eliminates any shuddering or jumping of the hands when the chronograph is engaged, and the column wheel offers precise control of the chronograph operation. A three-pointed hammer returns the hands back to zero in perfect synchronization when the chronograph is reset.” –Source
Accuracy of the 9SC5:
Seiko officially claims the accuracy of the caliber 9SC5 has an average daily rate of +8/-1 seconds per day in normal conditions.
Mean Daily Rate:
You may also see this movement quoted with a mean daily rate of +5/-3 sec/day. This is the mean (aka average) of the daily rates, before casing, tested in 6 positions in an “artificially controlled” (perfect?) environment for 12 days. In other words, not real life conditions and sounds good for marketing.
The caliber 9SC5 holds a power reserve of at least 72 hours/3 days. Grand Seiko claims that this is the longest power reserve in the industry today (with an asterisk that notes the claim is based on Grand Seiko research as of March 2023).
How many turns of the crown makes it a full power reserve?
Seiko does not appear to provide this information. If you have a watch with this caliber, please share your experience below.
How often does the 9SC5 need serviced?
The starting retail price of models with this movement is $13,700 USD.
Watches with this movement:
“Grand Seiko, you just trumped Rolex’s Daytona with this gem! And with a date window, and for less than half the price! Congratulations!” -BA on YouTube
- Grand Seiko 9SC5 official page
- Grand Seiko 9SC5 instruction manual (pdf)