Grand Seiko’s first all-mechanical complicated watch debuted in 2022. It was a timepiece with a movement featuring a tourbillon with an inner carriage rotating at eight beats per second and a constant-force mechanism rotating at one beat per second. Not only was the Grand Seiko Kodo Constant-Force Tourbillon SLGT003 a complicated and ingenious watch, but it was also quite the groovy one. The constant-force mechanism together with the beat of the escapement created a unique and steady beat that was hard to resist. I couldn’t sit still when I saw the watch during Watches and Wonders 2022. This year, Grand Seiko brought out a second version of the grooviest watch it ever created, the SLGT005, with its light aesthetic inspired by daybreak.

One Japanese word for “heartbeat” or “pulsation” is kodō (鼓動). It’s appropriate for a watch with such a distinct-sounding movement. When I first encountered the watch, its beat certainly made an impression on me. The Grand Seiko Kodo Constant-Force Tourbillon SLGT003 made such a big impression that it went on to win the Chronometry Prize at the GPHG. I think it also deserved an Emmy Award for its grooving movement. At 6 o’clock on the movement side, it reads “sixteenth note feel.” According to Drum Barossa, “16th note subdivisions [have] been played since the ’70s to create a funky feel” — in music, not watches. But one of Grand Seiko’s top watchmakers is an avid guitar player and a fan of jazz guitarist Mike Stern, who wrote the instrumental fusion classic “Sixteenth-note Feel.” The song features bassist John Patitucci and drummer Dave Weckl providing a subtle yet steady and grooving beat.

Grand Seiko Kodo Constant-Force Tourbillon

The groovy Grand Seiko Kodo Constant-force Tourbillon “Daybreak”

Mike Stern has Weckl to produce a funky beat. Grand Seiko has a tiny and very complicated mechanism to do so. The tourbillon of the caliber 9STL (SLGT003) and 9ST1 (SLGT005) has an inner carriage that rotates at eight beats per second, while the constant-force mechanism rotates at one beat per second. The construction — a constant-force mechanism that releases the energy from the mainspring in regular doses onto the movement with a tourbillon on the same axis — is unique. And so is the sound. It does indeed sound a lot like a minuscule drummer playing a rhythm of eight beats per second (the watch’s frequency) on a tiny cymbal ​​while hitting his piccolo snare drum every second. The result truly is a sixteenth-note feel.


But this caliber is not just a treat for the ears. Indeed, the open-worked movement inside the new Kodo Constant-force Tourbillon “Daybreak” is also a feast for the eyes. The “Daybreak” is a lighter-colored version of the first Kodo and shows movement components with a silver tone. This gives the watch a bright appearance that accentuates the intricately constructed and layered movement parts. The meticulously hand-polished components create a very pronounced look, and the use of blue sapphires instead of red rubies only ups the visual balance and spectacle. According to Grand Seiko, the pale blue hue of the sapphires is reminiscent of a beautiful dawn, and the airy color does indeed work very well with the chosen theme.


Platinum 950 and Brilliant Hard Titanium

The Kodo “Daybreak” comes in a 43.8 × 12.9mm case with a 50.6mm lug-to-lug length. GS uses platinum 950 for the inner case and Brilliant Hard Titanium, an alloy twice as hard as steel, for the outer one. The alloy will keep your Kodo highly resistant to scratches. That’s not a bad thing for a watch that will set you back €385,000 / US$365,000. Yes, just like a beat-up drum kit, it will continue to groove, and scratches won’t hurt the beat of the Kodo. But I doubt that Kodo owners only care about the sound.

Grand Seiko Kodo Constant-Force Tourbillon

And that’s completely understandable because the Kodo “Daybreak” is also a spectacular-looking watch. While the movement might be the highlight, the Zaratsu-polished parts of the case that create a distortion-free mirror finish are also hard to ignore. They contrast nicely with other parts that display a subtle, manually brushed hairline finish.

Maybe the boldest design decision was made when it came to finding the right strap for a watch inspired by the break of dawn. The off-white strap is made from a durable calfskin that, according to Grand Seiko, is “specially treated in the same traditional way once used in samurai armor.” The leather was tanned with natural materials to achieve a white color and received several layers of white urushi (Japanese lacquer) for a striking texture and sheen. If this is a bit too bold for the 20 buyers, the watch also comes with a charcoal-gray crocodile strap.


The beat goes on

GS’s second grand complication is again very exclusive and costly. But it also has a charismatic and striking yet balanced look, especially with the case’s open-worked lugs. Technically speaking, the second Kodo is also truly original and fascinating, and it will most definitely appeal to movement connoisseurs. On top of that, the Grand Seiko Kodo Constant-force Tourbillon “Daybreak” is incredibly groovy, of course.

Grand Seiko Kodo Constant-Force Tourbillon

You might also like to know that each of the 20 watches, of which delivery starts this December, has a movement that goes through 48 hours of testing in each position and at three different temperatures. The hand-winding caliber 9ST1 has a power reserve of 72 hours and an accuracy of +5/-3 seconds per day. The highlight of this micro-mechanical “beatbox” is, without a shadow of a doubt, the tourbillon and constant-force mechanism sitting on the same axis. Looking at the 12 o’clock position will tell you the time, but looking at 6 will give you timeless joy, especially in a quiet room There, the beat of the watch will get your head nodding and your hips shaking.

Kodo Constant-Force Tourbillon

Let me know in the comments if the groovy Grand Seiko Kodo Constant-force Tourbillon “Daybreak” is your jam too.

Watch specifications

Kodo Constant-Force Tourbillon “Daybreak”
Open-worked with offset time display at 12 o'clock
Case Material
Platinum 950 inner case and Brilliant Hard Titanium outer case with Zaratsu-polished and hairline finishes
Case Dimensions
43.8mm (diameter) × 50.6mm (lug-to-lug) × 12.9mm (thickness)
Box-shaped sapphire with anti-reflective coating on inner surface
Case Back
Platinum and sapphire crystal, affixed with screws
Grand Seiko 9ST1: manual-winding tourbillon caliber with constant-force mechanism, 28,800vph frequency, 72-hour power reserve with 50 hours of constant force, 44 jewels, mean daily accuracy of +5/-3 seconds
Water Resistance
10 bar (100 meters)
White calfskin with urushi (lacquer) coating and charcoal-gray alligator strap, 22mm width, platinum folding clasp with push-button release
Time (hours and minute hands, small seconds on the tourbillon) and power reserve indication
€385,000 / US$365,000