Without making any commotion about it, Seiko sneaked in another adaptation of the Marinemaster: the Prospex Marinemaster 300 SLA021J1.

The Marinemaster 300 was first experience with the more costly Seiko diver’s watches. I had a Sumo at that point, which I adored, yet then I had the opportunity to meet the Marinemaster 300 with reference SBDX001. It was a genuine shocker to perceive how Seiko had the option to help the €2000 sticker price it had. The review I composed back then , got one of our best-read articles ever. From that point forward, in mid 2015, the Marinemaster 300 turned into an exceptionally faithful companion on a considerable lot of my excursions. Both expertly and secretly, particularly when there was a pool or an ocean involved.

Marinemaster 300 SLA021J1

Later in 2015, maybe mid 2016, Seiko declared its replacement of the Marinemaster 300 SBDX001, the SBDX017. Michael Stockton composed an extensive article on his involvement in that improved form of my watch (however didn’t choose to get one, yet Gerard did). It was the point at which the Marinemaster 300 as such was ended, and supplanted by the green dialed SLA019J1 that wasn’t called a Marinemaster 300, that Michael chose to add one of these watches to his assortment too. He even held it close to a green Rolex Submariner ‘Hulk’, in this article . The SLA019J wasn’t just a green dial adaptation of the Marinemaster 300 SBDX017, it likewise had some new upgrades locally available, similar to a sapphire gem, rather than the Hardlex precious stone and an earthenware bezel, at last. As I composed in those days in my survey of the SLA019J1, I couldn’t envision a Seiko inventory without a legitimate replacement of the Marinemaster 300 SBDX017. It took some time, yet I am certain Seiko needed to have the focus on their green dial SLA019J1, restricted to 1968 pieces.

And at that point, there is the Marinemaster 300 SLA021J1 watch, in spite of the fact that it is formally not a ‘Marinemaster 300’ any longer. We mentioned this watch from Seiko to have a more intensive gander at it.

Ceramic Bezel

Two things that I saw and might want to begin with first:

  1. The lunette is fired (the Dutch press material expressed it was still steel). It is a similar material as the restricted version SLA019J1 model in green however in dark as it was before on the SBDX017 and the more seasoned SBDX001 for example.  Also, the gem is sapphire.
  2. The cost is €3200, equivalent to the green restricted release SLA019J1 reference.

They additionally relate a piece to one another obviously, as Seiko made it conceivable to come up with a green dial form with artistic for precisely the equivalent price.

I have the old Marinemaster 300 with steel bezel and even following a couple of long periods of utilization, including a few occasions, the bezel holds up quite well. There are a few scratches working on this issue and wristband, however the bezel is as yet 100% fine. In any case, I like the move up to clay. The cost is another theme. For the LE Seiko chose to remain firm at the €3200 sticker price for this watch like the green LE.  Sometimes, Seiko charges more for a LE and now and again not.  Comparing it to earlier MM300’s, the cost has expanded in strides since our first survey (€2000 for the SBDX001, €2350 for the SBDX017 which was later on expanded to €2500), it is a significant advance to €3200. Presently, the gem changed from Seiko’s own Hardlex to sapphire, which is undoubtedly an all the more expensive decision for a precious stone, yet it’s still an enormous bounce at the absolute contrast in cost. I believe that Seiko estimating has been reexamined and has expanded in general in the last 12 – year and a half. It generally used to be a great deal of significant worth for cash however, so let’s check whether this Seiko Marinemaster 300 SLA021J1 still is.

Caliber 8L35B Movement

I don’t need to focus in on the development for a really long time, as it is similar development as utilized in its archetypes. It is Seiko’s type 8L35 development, in view of the Grand Seiko 9S55. Indeed, the SBDX017 previously had a second cycle of the 8L35 development, alluded to as 8L35B. Some way or another in the authority public statement and data on the site, this is no place referenced. Be that as it may, when I visited the Grand Seiko fabricate, where this development (and watch) is likewise being delivered, it was certainly the 8L35B in the creation line. There are various enhancements over the 8L35, which is the utilization of MEMs innovation (which alludes to more tight resistance pieces that ought to take into account better timekeeping and less wear over the long haul). The force hold of the type 8L35B development is around 50 hours.  The 8L35B likewise has a somewhat unexpected completion in comparison to the 8L35 to the extent I recall, however you can’t see it in any case as it does not have a showcase case back. Somewhat disillusioning is the normal deviation that Seiko ensures for this watch, from – 10 to +15 seconds out of each day by and large. I feel that should be possible (much) better for a development like this.

Monobloc case

In actuality, there is no case back. The case comprises of two sections, the case and the bezel, so everything needs to come in (and go out) by means of the gem. The Seiko Marinemaster 300 SLA021J 1 uses the equivalent monobloc development as the past references, which is guaranteeing water obstruction and makes a helium valve (if you’d need one in any case) repetitive. Working on this issue back, there’s the ‘Big Wave’, or ‘tsunami’ logo in bas alleviation just as some etching concerning the reference number, chronic number, water obstruction and so forth In the event that you aren’t effectively mindful of this, the chronic number likewise shows the year and month where this watch was delivered. As should be obvious, the chronic number on ‘our’ watch begins with 91, implying that it was created in 2019 and in the primary month, to be careful (9 – 2019, 1 – January). Different numbers are only the ‘production’ number of the piece. Obviously, as an expert diver’s watch, the Marinemaster 300 SLA021J1 likewise has a screw-down crown, as imagined below.

Zaratsu cleaned case

Just like its more costly Prospex LX siblings, the instance of the Marinemaster 300 SLA021J1 is likewise wrapped up utilizing the Zaratsu cleaning strategy. This mirror edge cleaning is done in the assembling of Grand Seiko. The ‘zaratsu’ strategy, which name gets from the name of the machines utilized for this procedure, requires 3 years of preparing before one is adequately gifted to clean cases along these lines. Before, a few group complained that when you needed to have your watch repolished, it was impractical without having it dispatched to Japan. Indeed, that has changed as of late. Additionally at a portion of the neighborhood Seiko auxiliaries, there are gifted Zaratsu polishers nowadays. Since the SBDX017, the Marinemaster 300 is ensured with a super-hard covering. Seiko alludes to this as their ‘DiaShield’ treatment. So scratching the surfaces ought not be very easy.

The impact of the Zaratsu cleaning and the brushed surfaces is staggering. It is something that I appreciate the greater part of claiming a Marinemaster 300, or (Grand) Seiko when all is said in done. It is simply delightfully done and it is something of which you won’t ever get enough.

Dial and Hands

Just like the excellent of the case completing, the hands and dial are additionally made with the most extreme consideration and exactness in Japan. It isn’t acceptable with Grand Seiko, yet the hands have a wonderful brushed completion and I think the nature of imprinting on the dial is beyond what you can anticipate from a watch in this value class. It is with no imperfection, in any event, when utilizing a full scale focal point. Gracious, and I love the brushed silver hued date disc.

A part of you are exceptionally centered around the iridescence of hands and hour markers, and with Seiko, you realize this isn’t anything to stress over. Seiko utilizes their own Lumibrite composition, as Gerard clarified in this article . During low light conditions, or in the complete dull even, you will experience no difficulties perusing the time on this Marinemaster 300 SLA021J1. As you can see on our image beneath, the triangle and the initial 20 markers on the bezel are likewise luminous.


As you can see, the new Marinemaster 300 SLA021J additionally has some gold components added to the dial. This was additionally the situation with the green SLA019J1, however obviously, it’s something that Seiko clutch. Furthermore, frankly, I love it. It very well may be a little gesture to the previous SBDX012 (2012 50th commemoration version) and its unique 1969 reference 6159-7000 model, yet whatever it is, I truly burrow it. I’m not especially an aficionado of the Prospex logo on the dial. It replaces the past Marinemaster printing, however I rather would have seen it unfilled. I figure it would be more open than it is currently (or was previously). It’s simply a gratis plan tip.


Another thing that hasn’t changed is the arm band of this watch. The Speedmaster style arm band has been on the Marinemaster 300 from the beginning, and albeit the plan isn’t my top choice, the quality is fine. The fasten is as yet unchanged, with the expansion instrument that feels somewhat unstable, yet else, it is a strong wristband. The feebleness is principally brought about by the meager sheet of metal utilized for the catch expansion. Yet, what is tremendously irritating, is that it stretches out by pulling the flip-lock. This would be an incredible method of utilizing the diver’s augmentation, however when I take the wristband off, it happens as a rule, that I pull the flip-lock all in all too far back, and afterward the whole diver’s expansion comes out. I had wanted that Seiko would likewise receive the wristband style of the new Prospex LX models for this watch, that arm band is basically stunning.


At first sight, this SLA021J1 doesn’t appear to be especially unique from my own Marinemaster 300 SBDX001. Just when you look nearer, there are the little contrasts on the dial for instance. Or then again the way that this new reference has a sapphire gem and a ceramic bezel embed. Little things from a more noteworthy viewpoint, as I might suspect this watch is arriving at famous status, yet for the fans, these little contrasts are critical. I get that, and along these lines, I additionally accept that the cost of €3200 is supported. The previous cost made everybody go “This watch is extraordinary blast for the buck”, so now Seiko expanded the value, we ought not be crying over it. We generally said that this watch was a stunning purchase. Is it less astounding at this point? No, yet the refreshed value purpose of €3200,- places this watch into an alternate point of view. It is currently less ‘obvious’ to go with the SLA021J1 rather than that Tudor Black Bay, for example.

In the end, this watch is an extraordinary piece and can be a companion forever. It comes with a decent elastic tie, that feels a lot milder than the one that accompanied mine in 2015. It is a commendable replacement of the SBDX017, despite the fact that the means are little. However, maybe that’s what makes this watch a future icon.

More data through the authority Seiko Prospex .


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