Credits: Article and images by Joshua Munchow @ Quill & Pad. See the original article here - https://quillandpad.com/2023/12/06/grand-seiko-t0-constant-force-tourbillon-i-couldnt-believe-my-eyes-reprise-3/
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Common for many high-precision watches, Kawauchiya chose to use a free-sprung balance without a regulator. While more difficult to design and assemble, it reduces the chances of the timing changing after a strong shock to the balance since there are no regulating pins that can get bumped or fine adjustment that can dislodge or shift.
Combining this with a higher beat rate than most tourbillons have – and especially most constant force mechanisms – the balance is naturally less prone to variation.
A higher number of beats per hour helps any balance self-correct after a shock, and thanks to the preservation of angular momentum (a spinning object with mass wants to keep spinning and resist changing direction) any shocks will more quickly be averaged out.
It all comes together
After all this hard work and ingenuity to make a stable and consistent oscillator, how do you halt the mechanism to set the watch to the closest second and then get it going again without losing that accuracy?
Short answer: it is a difficult problem. However, Grand Seiko had also already solved that problem back in 1964 for a stopwatch used in the Summer Olympics in Tokyo.
The hacking feature basically assists the tourbillon carriage by giving it a push to start its rotation. And while that is important for a tourbillon beating at 2.5 Hz, it is crucial for the 4 Hz frequency of the T0.
When all of this comes together into the creation that is the T0 Constant Force Tourbillon, we have one incredible movement. It is also finished to a level that rivals most brands, reminding me of how Roger Dubuis finishes movements – and we all know that RD movements bear the Geneva Seal – so that shows the level Grand Seiko is attaining.
Even with the finishing being so well done, the true test is the chronometric performance since that was the entire purpose of creating the T0.
In lab conditions, the T0 Constant Force Tourbillon performed around +/-0.5 seconds per day, which comes out to a movement that is 99.9994 percent accurate. While it will surely not achieve those results under normal wrist conditions, it still is as good as – or better than – the Spring Drive, which is quartz regulated.
I don’t know about you, but I have absolutely no qualms calling this one of the pinnacles of 2020.
The only issue that remains is that it is a concept movement with no plans for commercialization (yet), even though the research and solutions will likely find their way into other models. But who knows: perhaps Grand Seiko will double down on this style of movement development and we will see a whole line of more avant-garde, experimental pieces designed to stir the pot a little bit.
Kawauchiya has hope that it will continue forward with development and that features from it will be utilized throughout Grand Seiko. I hope he is right.
But one thing is for sure: Grand Seiko finally did it. The T0 Constant Force Tourbillon is a masterpiece like all of the other Grand Seiko and Credor masterpieces that have come before, but it breaks the mold for Grand Seiko.
Hopefully there will be such a good reaction that it will boost the confidence of Grand Seiko to stretch its design legs and go for a run, and perhaps watch fans and collectors who haven’t given Grand Seiko its full due will join in.
The brand has so many incredible offerings, and the T0 Constant Force Tourbillon is just a sugar-coated appetizer to all the rest of what the brand has created.
The T0 Constant Force Tourbillon also isn’t a watch, but a movement (at time of writing), and is not for sale, so there’s no need to break it down any further. I’ll just say that I love this darn thing and I hope you all do too! Since then the Grand Seiko Kodo Constant Force Tourbillon has been released and won the Chronometery prize at the 2022 Grand Prix d’Horlogerie de Genève (GPHG).
For more information, please visit www.grand-seiko.com/us-en/special/T0-story.
* This article was first published on December 27, 2020 at Grand Seiko T0 Constant Force Tourbillon: I Couldn’t Believe My Eyes.
Quick Facts Grand Seiko T0 Constant Force Tourbillon
Movement: manual winding Caliber T0 Constant Force Tourbillon, 72 hours power reserve, 28,800 vph/4Hz Hz frequency, free-sprung balance in 60 second, constant force tourbillon, constant force mechanism
Functions: hours, minutes, deadbeat hacking seconds; power reserve indicator
Limitation: concept movement
Price: not for sale
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Credits: Article and images by Joshua Munchow @ Quill & Pad. See the original article here - https://quillandpad.com/2023/12/06/grand-seiko-t0-constant-force-tourbillon-i-couldnt-believe-my-eyes-reprise-3/