Seiko Flightmaster Chronograph 6S37 SBDS003: The Grand Seiko Mechanical Chronograph that never was

“Most of us march out our lives steadily to the beat of that seconds hand, ever in synch with time. While some are seemingly unaware of its passing, others look upon it with detached disinterest, and yet others with endless fascination. For those of us who are fascinated, we are ever trying to come to grips with this untouchable force. We can watch a seconds hand turn endlessly, see the crest of time as it flows in waves — one second ago gone forever and one second to come suddenly here. In trying to grasp this passing, this endless flow, we have invented “a clock within a clock,” not to stop time, but to catch a glimpse of it. The chronograph, more properly chronoscope, allows us to capture, like the ephemeral last breath of a dying man, a tiny slice of time — perhaps really just a snapshot of the wake of its passing. Yes, they are tools designed to help us to manage and break up time in the pursuit of our day-to-day activities, but there is also deeper symbolism — though perhaps we too prefer to play in ignorance.”

Taken from Carlos Perez’s excellent article on chronographs “The Cats and the Clock

Currently, the Grand Seiko range of watches remains simple time only watches, with the exception of the GMT and Chronograph models. However, although the GMT Grand Seiko is available in both Spring Drive and Mechanical variants, the same cannot be said for the Grand Seiko Chronograph, which is currently only available in the Spring Drive variant.

SBGC001 GS SD Chronograph

SBGC001 GS SD Chronograph



SBGM003 GS GMT Mechanical

SBGM003 GS Mechanical GMT – Taken from Yeoman’s blog

However, all is not lost for purist chronograph fanatics. There do exist a chronograph calibre that is derived from the Grand Seiko 9S family, although it is not labelled as such and is found in much sportier ranges. However it is not easily available nor obtainable these days.

I am of course referring to the 6S family of Seiko chronographs. At the time of writing, all current Seiko mechanical chronographs are using the 8R family of movement, and sad to say the 6S family is no longer in use by Seiko. However it lives on as Junghans Calibre J890 and also as Tag Heuer’s Calibre 1887.

In a recent post at the Seiko and Citizen forum, Noah did a tear down complete with pictures, where he believes that the 6S shares the same lineage as the 9S / 8L family of movements. If true (I’m no trained watch maker to make affirmative statements about any of this!), this would then make the 6S chronograph calibre the Grand Seiko Mechanical Chronograph that never was!

The Seiko 6S movement was first released in 1998, which is also the same time that the Grand Seiko 9S and the equivalent unadjusted 8L movements were released.

Variants of the 6S movements

6S37 & 6S77 are 40 jeweled movements and rhodium plated

6S78 is a gold plated movement, lacks the power reserve indicator and has 34 jewels
6S28 is rhodium plated and lacks the power reserve indicator. This is also the last 6S variant in production before the entire 6S family was discontinued.

6S74 is a 35 jewel gold plated movement and handwind only

6S99 is a 35 jewel limited edition skeleton movement made for a Credor


There are actually 3 variants of the automatic Flightmaster and all uses the 6S37 movement, all 3 being released between 2001 and 2003. They are encased in full Brightz Titanium including the bracelet.  Current production Flightmaster (at the time of writing) are using quartz movements.

• Automatic 6S37 28,800 bpm
• Slide rule bezel for flight calculations (SBDS003 only)
• Column wheel chrono mechanism with tilting pinion
• 50 hour power reserve
• 1/8th second chrono function
• 30 minute meter
• 12 hour meter
• Brightz Titanium case, bezel and bracelet
• Non-reflective black paint to the dial
• Dual curved Sapphire crystal
• A/R coating to the crystal
• See through case back made of Sapphire crystal
• 100 meter water resistance rating
• Screw down locking crown
• Screw down locking chrono buttons
• Anti-magnetic ability
• 44mm w/ crown
• 14.8mm thick
• weight : 128grams
• 300+ parts in its construction
• Accuracy +15/-10 seconds a day

SBDS001 is a non-limited edition.

SBDS002 is a limited edition (300), brown dial, bezel and bracelet link variant.

SBDS003 is a limited edition (300), with a different bezel from the earlier two. The date window cut out is also cleverly hidden at the 6 o’clock position as part of the 12 hour subdial. The other 2 variants have the date window cut out at the 4 o’clock position. Also this variant comes with arabic hour markers compared to the stick hour markers of the other variants.

In addition, the rotor of this variant is also different. More will be mentioned on this later.

This variant shall be the focus of this post.

SBDS003 (L) SBDS002 (R)

SBDS003 (L) SBDS002 (R)

SBDS001 (L) SBDS003 (C) SBDS002 (R)

SBDS001 (L) SBDS003 (C) SBDS002 (R)

Case finishing


As always the Brightz Titanium finishing used by Seiko is nearly indistinguishable from polished stainless steel. Without knowing more about the watch, I initially also thought I was handling a full stainless steel watch until I glimpsed the words “Titanium” etched on the case back.
IMG_0008 IMG_0009 (1)



The bracelet comes with solid end links and bracelet links. The clasp is machined (not stamped) without any extension, as compared to the extending clasp that comes with the Marinemaster 300 and Landmaster watches.
The flightmaster is not all polished as you can see in the picture above. At the lugs, the top of the lug is brushed vertically while the sides are highly polished. Note the absence of drilled lugs.
IMG_0013 (1)

Being a chronograph, the three button configuration on the right side of the dial should be familiar to watch consumers. They are highly polished and are able to screw down in order to prevent accidental activation of the chronograph, accidental stoppage of the process of measuring the time once the chronograph has been activated or the accidental resetting of the measured time.

IMG_0012 (1)

The crown is signed “S” and is also screwed down.

Another point that I would like to highlight here is how the bezel is secured to the watch. It is not simply an insert, but screwed on to the case itself. This can be seen in the “extension” of the bezel that screws down on either side of the crown.

IMG_0016 (1)

This is repeated on the non-crown side of the watch as well.

Bezel, Dial and Hands

Bezel Marking

Bezel Marking

The bezel of the SBDS003 differs from the other 2 variants as it is a slide rule for calculation of various flight functions. I do see weight and distance measurements marked on it, but I do not profess to know exactly how it functions. However I must say that aesthetically the bezel is very well done with all the numbers and hash markers etched into the titanium bezel and then painted white, while the background color of the bezel remains black. There is also no discoloration, peeling or chipping of any kind that I noticed. The colors on bezel has a glossy look to it but do not attract fingerprints.

30 minute counter

30 minute counter

Constant seconds

Constant seconds

12 hour counter + hidden date window

12 hour counter + hidden date window

The date window is very subtly hidden as part of the 12 hour counter right at the 6 o’clock position. This makes the dial slightly less cluttered as compared to the other 2 variants. Seiko should adopt this design more often.

Flightmaster logo

Flightmaster logo

In line with the nature of Prospex watches, you will notice there there are no applied markers on the watch in order to minimise reflection when reading the dial. This also applies to the logo which is very simply printed ” Seiko Flight Master Automatic” across 3 lines.

Power reserve

Power reserve

As with all 6S movements, it comes with a 50 hr power reserve and this is reflected as such in the power reserve indicator.



The hands are color coded. For instance the chronograph hands (center seconds, 30 min counter and 12 hour counter) are all painted in yellow, while the non-chronograph hands (hour hand, minute hand and constant seconds) are all painted white. This makes it very easy for the user to distinguish very quickly the relevant information that is required.

Lume shot

Lume shot

Lume shot

Lume shot

The hour markers, hour, minute and the tip of the center second hands are all lumed, but obviously the lume will not be as bright as that compared to the Marinemaster series.


I highly recommend taking a look at the references provided below for Randall and Noel’s posts as they give a detailed tear down of the 6S movement. Randall took apart a Flightmaster while Noel took apart a Credor Chronograph. Both contain slightly different variants of the 6S movement.

Column wheel seen at the 12 o’clock position. The rotor is also engraved with a sea eagle. I believe this is unique to the SBDS003 rotor and clasp.
IMG_0005 (2)-revised
Balance wheel seen at the 4 o’clock position.
IMG_0006 (2)-revised


The 6S chronograph is an excellent movement given that it is based on the 9S Grand Seiko movement. Unfortunately it had just been completely replaced by the 8R chronograph family. It was very telling that just before its discontinuation, all 6S equipped chronograph watches sell for a higher price than their 8R cousins and were only available as Japan Domestic Models (JDM).

The prior automatic Flightmaster series were also a very attractive range of watches to collect given that the latest models are quartz driven. The finishing of the watch case and dial are definitely something to be seen in the flesh.

Perhaps it is fitting that the top end 6S chronograph movement variants were never placed in a Grand Seiko, but rather in watches that were even rarer and harder to obtain, being the Credor Phoenixes and automatic Flightmasters.

Thanks to J for loaning his Flightmaster to me and permission to use his group shots of the 3 Flightmasters!

Selected references

Watchuseek post revealing that Tag Heuer’s 1887 was a Seiko 6S37 –

Noel’s breakdown of a Credor Chrono found on Seiko and Citizen Forum –

Carlos Perez’s article on chronographs:

Excellent post on all 3 automatic Flightmasters and the 6S variants:

Randall’s breakdown of a Flightmaster with movement shots and his thoughts –


3 thoughts on “Seiko Flightmaster Chronograph 6S37 SBDS003: The Grand Seiko Mechanical Chronograph that never was

  1. Pingback: Interesting Seiko finds on the Bay: Credor 6S74 Chronograph Platinum and Brightz 4S27 Titanium | musingsofawatchaddict

  2. Pingback: Seiko Special - SNZH57 Fifty Five Fathoms Review, SKX007 6 Month Update & An Automatic Flightmaster - Survival Gear

  3. Pingback: Seiko SNA411 “Flighmaster” – SaFonaGastroCrono

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