Grand Seiko SLGA015 Spring Drive 120 Hour Titanium Diver Review

My new SLGA015 arrived more than a week ago, and after continuously wearing, I collected personal observations to share with fellow crunchers.

My nearest AD is more than a 3 hour drive, so I actually bought this from a remote AD having based the decision on nothing more than internet research.   Many of the aesthetic and tactile experiences came only after receiving it, all of which were a pleasant surprise.

Honestly, aesthetics are just a bonus of which I tend to dress down when I can. I bought the watch because I love the new tech spring drive, and I'm partial to dive style watches.  Gear speed regulation applied from a frictionless sinusoidal magnetic pulse sync’ing braking, regulated by the oscillation of a temperature compensated home grown quartz crystal vibration which is induced from the conversion of kinetic energy into electrical…. All of which will go on forever as long as the dual main spring kinetic power reserve indicator complication doesn’t show empty.   Very cool!

After checking time variance daily since I got it, there are no surprises here to me.   As has been my experience with other Seiko movements,  it seems here too GS might have grossly undersold their error rate on this 9RA5….either that, or they snuck a cesium decay movement into this watch.   I have not measured any daily variance.  All of my daily measurements so far have been dead on  within my expected best human reaction time.   I set the watch on the day I got it, and never hacked it again.    This temp compensated version of the spring drive has a paper target of 10sec/month accuracy.   Extrapolating on what I measure so far,  I won’t be surprised if the mean is an order of magnitude or more  better.   

Regarding aesthetics and attention to detail:

The Kuroshio current (or black stream) dial, is more subtle than I expected being a reflective texture, that appears and disappears depending on how the light hits it.  It’s not 3-D textured, but rather has an optically textured dark iridescence view that is visible when the light source hits it at particular angles.  The fluidity of the appearance/disappearance is not unlike what one would expect dark water…. “Black stream” name for it seems fitting.

Each of the numeral lume points is surrounded by a mirror like polished metal ring.   The mirror finish reflect the dark underside  of the gliding second hand and catches ones eye.  With an opposing light at a distance, the mirror polished ring lume points will sparkle not-unlike a white gem and catch ones eye.  This aspects is problematic if one likes to dress it down like I tend to do.  Inconspicuous is not its strength especially with the even more sparkle from the titanium bracelet.

Lume is exceptional this diver, though that's no surprise given seiko is known for that .

Other little  observations:

The date in the font window isn't just printed, they are actually raised numbers with a sheen and clear edging and high contrast.

Even the tiny power reserve indicator is polished to the point of being reflective, and appears to be composed of a nub and spoke, an unexpected complexity that differentiates itself from what one might otherwise expect to be a typical stamped metal pointer.

I love the little red warning marker on the stem seen when the crown is pulled out to worn you that your crown is open.

The SLGA001 didn't have a ceramic bezel, and the used market for those shows one why you want one.  The ceramic bezel on the SLGA015 is shiny reflective black outer with recessed white numerals, and couldn't be easier to read.

I've always been partial to dive watches, which typically come with a momentum that I can feel when I move my arm around quickly. While I never thought of that momentum as a feature it was also never a negative.  The 30-40% weight reduction (depending on the literature) from the us of titanium, feels on my wrist more like a typical non-diver chronograph,. i.e.  it's there with noticeably reduced momentum. The difference is welcome though not a big deal.  My turtle feels slightly more massive on the wrist than the SLGA015.

I like the 5 day power reserve indicator a lot.  It tells me that the wrist movements from my normal activity at my desk job is just barely enough on good days to maintain reserve levels.  The overwind escape mechanism has no fear of being worn out by me.  On a busy weekend day, I can add an extra day to my reserve.   As expected, the meter seems to decrease by a 1/3 of a day between when I go to bed and when I wake, i.e. it appears to be accurate.     It seems that doing dishes and folding laundry are very good at charging up an automatic watch.  Further the PR makes for an excellent mechanical “Close your rings” type complication, achieving a daily activity goal/level, assuming of course one forgoes manual winding or an auto winder.   I won’t explain that phrase here 😜, but it’s a good thing.   

Regarding diving aspect… I am a certified diver, but I think it unlikely this watch would ever be my first choice to go diving with.  If for some unusual reason I were to use a watch instead of a wrist dive computer, I’d probably grab my turtle first, since when diving, the last thing I want to be think about is accidentally banging my watch on the boat, tanks, rocks, coral or the post affects of salt water.   That said, I think a diver timing bezel is handy low tech timer with very high failure resistance and is just fine for tracking plunge time of my coffee French press, or when it’s time to pick up the take out pizza.   The black shiny ceramic bezel with inset white numerals is beautiful, polished and contrasty, and is supposedly cushioned from behind to mitigate impact breakage.   I gives the appearance that combat battle scars that imply its mettle has been tested through past rough adventure…this isn’t likely to be it’s thing.  It looks like the polished finished will have some longevity.

The second place contender for my purchase was an SLGA001, which is the most similar model to this one.  It was a 60th anniversary limited edition of 700 that came out in 2020, and was the first diver with the 9RA5, movement but oriented so that the date is at 4 o’clock, and power reserve at 10 o’clock, and lacks a ceramic bezel which was highlighted in that many of the used ones I saw had scuffed up bezels.

In hind site, practically speaking, power reserve at 10 o’clock on the SLGA001 would work better for my current schedule.  At 9 o’clock on the dial where it is on the SLGA015, it’s difficult to read the power reserve between 7:30 until almost 9 because of the fat hour hand, which unfortunately corresponds with the time I typically put my watch on.   Perhaps in time, it won’t be the first thing I want to look at when I put it on in the morning.

Though the case is very durable high-intensity Titanium.   I wonder if the bracelet is the same grade of titanium.   Most of the time I wear it dressed down with a NATO, though the first day I wore it with the bracelet, and while consciously trying to be careful not to scratch the clasp on the first day, 24-hours later, the clasp no longer looked factory immaculate.   I’m not concerned, but was surprised that it was unavoidable for a day.   Literature says the high-intensity titanium is not surface hardened, meaning that if anyone wanted to, they can polish out any usage scratches.  It appears only the corner edges of the watch case are Zaratsu polished, so no Zaratsu polisher needed for the bracelet clasp.

Dimension specs 22mm band, lug to lug 51mm, 45mm diameter, 14mm height.