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Reliving the Golden Age of the Professional Diver: The Baby M.M.

Reliving the Golden Age of the Professional Diver: The Baby M.M. "Reduced" Story (Part 1)

An in-depth look at the SBDC125 and SBDC127 and how it compares to the uber Marine Master 300
Published by: Samuel Ng
Mar 19, 2021


In 2020, Seiko released a streak of novelties throughout the year. Here at Gnomon, we've broken down several of the new releases - from the Prospex "62MAS" Re-issues Ref. SBDC101 and SBDC105, to the supreme Rose Gold Emperor Tuna SBDX038, that sits atop the Prospex throne. Although 2020 has been intensely unforgiving to the world, Seiko persevered, and the outcome has been pretty fruitful. Within the spectrum of these new re-issue releases, a final hit before closing the year was the company's effort to reinstate its dive watchmaking pedigree. And yes, Seiko took us by surprise with yet another new Baby MM 200 duos: the Prospex 200m Diver Ref.125 and 127.

(The last drop from Seiko to close 2020) (Left: SBDC127, Right: SBDC125)

In an unprecedented and distressing year, amid a pandemic that hit the world hard, the already tumultuous watch space was not spared by. The preeminent Seiko persevered, though, by introducing a fantastic duo at a time when the watch world desperately needed them. Not slouching in any areas, Seiko again tastefully updated its iconic monocoque dive watch from 196, solely based on an atypical style, just like the brazen Tuna dive watches. The Prospex 200M Automatic "Baby MM Reduced" Ref. 125 and 127 reveals Seiko's relentless pursuit of both quality and beauty - a language where the perfect blend of form and function takes place - a work of horological significance for the Japanese watchmaker.

Indeed, the two dive watches are not officially considered true "Marine Masters" like the SBDX001, SBDX017, and the latest generation SBDX023, as they don't derive directly from those trios with Grand Seiko automatic caliber—
a better, luxurious build, where their dials used to be printed with the same moniker. But that was intentionally done by Seiko for specific reasons, which we will get to later. Despite that, we'd argue that both the SBDC125 and 127 do come real close to them. With an execution closer than their former variants, the SBDC061 and 63, all four musketeers brought the sixties Ref. 6215 and 6159 to mind, the newer versions more significantly. Although the familiarities derived from the predecessors, the Baby MM Reduced variants are built with modern specifications.

(A second generation MM200 SBDC127 beside the first generation special edition's SBDC065)

In this article, we'll be covering the two modern interpretations of Seiko's first "Professional" dive watches in-depth. Instead of a direct comparison with their Prospex lineage, the previous SBDC06X, we felt that the first Gen Baby MM200s were more of their own look – so a direct side to side comparison to its bigger brother would be much more stimulating. Who knows, we might even be able to answer the inevitable question of whether the SBDC12X comes close or is even a better value proposition than the uber MM300 SBDX023. When we rule out both the movements and the ratcheting-extension clasp, the observation we've made are rather astonishing.

At the end of the article, we conclude that the newly designed 6215/6159 re-issues are the right mix of the past with several unique touches that make them both as great on their own. And as a "reduced" variation, it graces the wrist more ideally than the beastly built SBDX023 without cutting corners. Instead, it exemplifies a good bump in Seiko's finishing and execution that accentuates the Prospex line as a whole. That said, we perceived Seiko as paying close attention to each and every detail when developing one of the brand's most iconic designs.

Let's Get Serious

Before we dive into the main topic on this new rendition of the Baby MMs, we first need to bring ourselves through their progenitor's historical perspective and also discuss how the genteel MarineMasters came about in the Japan watchmaker's timeline. Ok, so before developing the first "MM" in 1965, Seiko debuted the first legendary dive watch for recreational divers, which we all know is the 62MAS dive watchTo learn more about this, you can check our article on its history right here.

(Seiko's first proper dive watch for skin divers - the 62MAS) (Photo Credit: Hodinkee)

The 150m water-resistant dive watch was as good as it got during the rise of skin-diving. However, deep down, Seiko has now acknowledged their capability to develop a dive watch that's considerably more "serious." Indeed, we all know that the company that prides itself on a tremendous amount of professional dive watches today but was still lacking a serious dive watch at that time. They promptly needed one to cater to the professional divers' market. Not wanting to be stuck at a padawan level in dive-watchmaking, the company decisively started to work on a professional dive watch that functions at greater depth.

"A Seiko diver is unmistakable with its uniquely positioned crown, no bullsh*t looks, bold bezel, and elongated case design. And guess what? It all started with the 6215." - Michael Stockton, Fratello Magazine

It didn't take long for the East's esteemed watchmaker to prevail with a saturation dive watch for the world. Seiko debuted what would later carry the "MarineMaster" sobriquet in just a short two years, influencing many more Seiko divers to come. The Ref. 6215-7000 is the first professional dive watch with several ingenious upgrades. Measuring at 43.5mm, the 6215 is a behemoth; almost Panerai-ishly sized for that time when 34mm-36mm were the ideal men size watch. However, it got the job done, flexing a 300m water resistance, thanks to some prowess in its design. Several engineering feats were a first at that time - Seiko developed a front-loading case known as "monocoque case," whereby the entire case is milled out in one solid block with no cut out on its back like traditional timepieces. Through this method, the 6215 has a much lesser entry point for dust or moisture to penetrate, resulting in a robust build.

(The first "professional" Seiko diver - Ref.6215-7000) (Photo Credit: SJX Watches)

"Just think about that. Think about how seriously Seiko took this watch all those years ago – the effort that went into its design and testing, its use on the first-ever dive in Antarctic waters by members of the JARE expeditions." Gerald Donovan, TheGrandSeikoGuy

That's not all. Seiko upgraded the glass material to a "hardened" Hardlex mineral crystal from the acrylic ones found on the 62MAS. And for the first time, again, a large knurled unsigned crown was placed at the 4 'o clock position, allowing the watch to sit on the wrist with better ergonomics. A conventional diver's minute bezel is fitted from the top after the movement and dial are set in. Its uniquely marked with a countdown minute sequence, an inverse from the usual elapsed diver's minute one. Seiko relished a little flair for its dial with all these functional elements by adding a healthy dose of guilt markers, date frame, and handset, even for its debuted traffic light-seconds hand.

(A monocoque case that sets out to minimized water-penetration points) (Photo Credit: Watches For Life)

Let's not forget Seiko's continuation of the then Grand Seiko caliber within, their first automatic and 35-jewel 6215 calibers. The movement ticks at 18,800BPH and comes with a date adjustment function. The 6200 series was in production between 1964 to 1969, famous within the 62MAS, this particular 6215, and the 966 62GS Ref. 6245-9000 and Ref 6246-9000. With that said, all these elements in the 6215-7000 became a symbolic expression of Seiko's vision in designing professional dive watches.

(The 6216 caliber within the first "Marinemaster") (Photo Credit: The Watch Bloke)

The "Professional" Updates

"Forget the 62MAS, forget the Willard, the Turtle, and so forth. Yes, there are shades of those watches in other Seiko models, but the 6159 really set the pace." - Michael Stockton, Fratello Magazine

(The 6159-7001, first-ever professional dive watch acknowledged by Seiko themselves)

It wasn't long before Seiko updated their first 300m dive watch. They did so too quickly, in fact. After a year or so in production, the 6215-7000 was promptly replaced permanently by the 6159-7000 in 1967. Although virtually identical to its predecessor in looks, the 6159-7000 is executed differently. The dimension was up now to 44mm while keeping the single-piece case - with a one-piece bezel now available with both a count-up or countdown marking - of which the latter is more apt for professional diving.

(The appropriate countdown bezel on the 6159s) (Photo Credit: The Watch Bloke)

The markers and handset are kept gilt like before. The 12 o'clock fan-shaped indicator gets partition in the middle, an element that has been sealed in many of Seiko's dive watches since then. Another notable difference can be acknowledged through the "Hi-Beat" text printed right below the applied Seiko logo and "Automatic" text. This one word indicates what's keeping leviathan dive watch beating. Now clad with Seiko's mastery in Hi-beat movement, whereby the automatic caliber doubles up in beat-rate at 36,000BPH.

(The high beat 6159A Caliber inside the 6159-7000/7001 dive watches) (Photo Credit: The Watch Bloke)

Produced by Suwa Seikosha (the same facility that worked on the 6159 divers), the 25 jewels 6159A is the first hi-beat, automatic movement from Seiko, whereas the 6100 are famed for being used within the Grand Seiko family, bestowing capability to power the finest Grand Seiko VFA (Very Finely Adjusted) variants. We have to know the strenuous efforts to regulate and adjust a hi-beat movement in any given scenario. These VFA boys are tuned to an unbelievable +/- 2 seconds per day, guaranteeing an accuracy within a minute per month for the first two years of ownership. In addition, the second hands almost "glide" as compared to ticking ones.

This illustrates just how good Seiko's first automatic high beat rate movement can be. You might now think this finely adjusted caliber was meant for the more delicate and luxurious timepieces back then, but you would be dead wrong. The 6159-7000 boasts one within the same caliber family, where Seiko demonstrated the movement is equally robust for professional use.

(The legendary VFA Grand Seiko Reference 6186-010) (Photo Credit: The Grand Seiko Guy)

Aside from the higher beat rates, the diver boasts what might seem like a norm now - a quick date adjustment setting along with the ability to hand-wind, all through its crown at 4 o'clock position. Now the world gets the first monobloc, 300m dive watch with hand winding function in the adjustable-date. This automatic movement beats at 36000BPH (when 18,800 and 21,600PBH were standard back then) from Seiko. That's what I call impressive engineering.

The 6159-7000 was also the first to bear the "professional" insignia, both officially by Seiko in their parts catalog and on its no-nonsense matte black dial. Again, it was only produced for a year before being replaced by the 6159-7001, which is identical in both its look and construction to its prior. But rumor had it that this improved version was the only available outside of Japan, particularly in the North-America market. Simultaneously, the previous 6215 and 6159-7000 were only available within the country of the rising sun.

Back From Brink Of Extinction

Sadly, these two masterpieces were in production for only two years altogether, from 1968 to 1969, resulting in two of the grails for Seiko dive watch collectors. A plausible guess would be that Seiko received a professional diver's letter in1968 where he claimed that there were no watches, including the ones from themselves, that could survive the depth of 350m. And Seiko dropped the 300m dive watches and developed the "Tunas" with their ingenious outer-shrouds and L-shaped gaskets to take on oceans' depth. As history was written, on the bright side, the prominent, charming case lines and construction were not totally forgotten just yet.

(The development of this Grandfather Tuna ref. 6159-7010 that almost placed the monocoque-case diver into extinction) (Photo Credit: Monochrome Watches)

(The first-ever "MarineMaster") (Photo Credit: Watchuseek)

Subsequently, throughout the years, Seiko has kept churning new professional dive watches within the PROSPEX line. Even some with ever-reliable quartz movements and innovative dive-watch advancements. But a dive watch imbuing the redolent DNA of the 6159s and 6215 were missing. At some point, it might have seemed that their legacy was forever extinct, at least for thirty-one years or so. Seiko had several deep-diving machines like the saturation-fitting Tunas, the seventies C-shaped case divers ref. 6105-8110/8119, the 6306/6309 series, which are also known as the turtles, and of course, don't forget the Pre-SKX diver era led by the ref. 7548 series in the eighties. We got to know that the latter three series, which were rated at 150m water-resistant, whereas the Tunas started from 600m onwards. Although most of them carried a small shadow of the 6215 and 6159s, casting some of their design elements within the others, Seiko knew for a long time that they had to design one to fill the missing gap— a diving watch that hits the sweet spot and carries the 300m water-resistant baton.

Therefore in the year 2000, Seiko released, or should I say re-issued, their iconic 300m "professional" dive watch: the SBDX001, more commonly known to the market as the uber MM300. What a relief it was for Seiko lovers, enthusing the comeback of the single-piece case, with its distinctive case lines. The sobriquet came about and stuck within our heads perhaps because, for the first time, Seiko labeled its genteel 300m dive watch with the 'MarineMaster' moniker on its dial. Seiko had gussied up the quintessential tool for both professionals and desk-divers, that's not a slacker like those 150-200m "recreational" divers or the over-the-edge Tunas conceived for heavy-duty purposes. The Marinemaster 300 accomplished a perfect balance between those two types with remarkable quality both inside and out. And it doesn't wear like a giant hockey puck on the wrist.

(A more practical sized, professional dive watch) (Photo Credit: Strap Code)

About its punctilious appearance, the MM300 is an essential dive-watch, built for professionals just like before, executed now with sharper finishings, never seen before within the PROSPEX line. It now gets well-defined polishing on its 44mm case (staying true to original sizing), only to be separated by a finely stained mid-case with fluid case lines. Another detailed redux was the number of flat polished surfaces of the predecessors. The screw-in crown was placed at 4 o'clock and left unsigned, just like the 6159s.

As the inaugurated SBDX001 was part of the PROSPEX dive watch collection, the MM300's back now had the center spot with its iconic tsunami emblem and essentials engraved surrounding. A more accurate tribute to the 6159-700, let's not forget the iconic markers and handset on its dial, coated now with ivory-colored Lumibrite for luminance. The bezel's aesthetic and development are almost identical to the 6159s but suited to a modern theme. It is made out of single stainless steel material. The surface diver's markings are done with lacquer, permeating a shimmering gloss.

When everything seems to be a remake and design based on the past, the Seiko design team decided to clad the Marinemaster diver with a stainless steel bracelet executed in the same manner as its case. This bracelet is ingeniously designed with a ratcheting-clasp that allows a diver to adjust and extend out with precision onto the dive suit without any hassle. Never before did any other PROSPEX divers get this top-notch stainless steel bracelet with its diver-extension mechanism. And it is by far a much better-executed one compared to any other bracelets within Seiko's sports models, which many Seiko enthusiasts can vouch for.

(The ingenious ratcheting-clasp)

Last but not least, Seiko didn't hold back on anything and went full-throttle on this one. They placed the automatic 8L35 caliber into its single-block case, and it was the first to get one, along with the 1000 pieces Limited Edition 600m Tuna ref. SBDX005. I have mentioned quite a bit about the 8L35 movement, which can be seen here (INPUT EMPEROR TUNA BLOG). In a nutshell, it's Seiko's top-of-the-game automatic caliber deriving from the Grand Seiko's mechanical 9S55 caliber. Now we have a classic diver that oozes quality, almost flawless in both form and function, on the outside and inside.

(The legendary 8L35 automatic movement) (Photo Credit: Strap Code)

Sealing the "MarineMaster" Look

Of course, Seiko knew they hit a home run with the SBDX001 as it was one of the most extended production models since its release. However, its time was due for an update after fifteen years. One thing that the original MM300 has nailed is its workmanship, within a price point that's considered very well-worth it during its run, surpassing the Noughties. Fans were curious about the whats and hows of Seiko "making better" one of their almost-perfect in execution dive watches. All that we know is it was time to refresh the MM300, and we have gotten the SBDX017.

(A second-gen MM300)

The updated SBDX017 kept almost everything intact, only some minor upgrades on its aesthetics and movement. Seiko carefully tweaked the new MM300 by applying greater Lumibrite luminous on the markers and handset and subtly adding the PROSPEX "X" emblem on the signature 4 o'clock crown. Yes, I have heard whining about "why the hell would Seiko do that?" My strong defensive judgment would be that the watchmaker has a yen to remind us that they take their PROSPEX collection seriously. And the MM300 (or any other Marinemasters) has been in it since day one. I strongly think we should respect this decision where Seiko ties this sought-after diver with their professional line.

The second-gen MM300 also gets the proprietary DIASHIELD coating for better scratch-resistance, both on the case and bracelet. If you are interested in finding out more, I have gone through it quite thoroughly here ( INPUT SEIKO SARX055 BLOG LINK). Apart from the exterior, another upgrade is done on the inside. The "GS" caliber gets parts made with MEMS technology. It is a skill that was first used fully in the Grand Seiko division. Since the caliber is now part of the family, the 8L35 gets the same treatment. The technology delivers two to fivefold more precisely, whereby the mechanical parts are manufactured more durably than machined ones.

Subsequently, after three years in production, the SBDX017 has gotten yet another modern upgrade with two limited editions: the 1968 piece LE MM300 ref. SBDX021 with forest green theme, and the true to 6159-7001 re-issue ref. SBEX007 that's limited to 1500 pieces. The latter displayed Seiko's capability to seal the deal on the Marinemaster 300 heritage, even up to the hi-beat movement. The SBDX021 hoods the "GS" 8L55 caliber, beating away the same rate as the original 6159s. In fact, this particular one had won the Sports Watch Prize category the same year, at the 2018 Grand Prix d'Horlogerie de Genève. However, I would like to focus more on the SBDX021 in this article. Why? Because it was released with a significant change, inspiring the current MM300 generation—none other than the SBDX023 born in November 2018.

(The 2018 SBDX023)

Deriving from the Green MM300 LE, the SBDX023 has gotten a facelift on its outlook. At the time, Seiko had replaced the 'Marinemaster" label on its dial with the PROSPEX "X" logo, that in an honest opinion, did not actually affect its aura as one of them, as such things go. It's still an MM300 through-and-through, and it now comes with a ceramic bezel for better scratch-resistance and a set of greener Lumibrite that glows ever so brightly. The second hand is done in gilt to radiate some hint of the old-school 6159 charm alongside a two-tone handset, matching the "300m" label right below the "Professional" word. Oh, and don't forget another first application by Seiko with a sapphire crystal instead of their Hardlex mineral glass.

Consequently, with such upgrades on the Marinemaster 300, so did the price tag that came along with it increase. Other than that, the SBDX017 and SBDX023 have stayed true to their predecessors from the sixties. They are classified as the uber MM300 without compromising its appeal despite several modern tweaks to them.

Birth of the Baby Marinemaster

(The first Baby MM 200 SBDC061)

Although in some way justifiable for its pricing, the SBDX023 is in another ballpark of sports watches. It's in a price bracket that consists of those renowned Swiss brands, like Tudor's Black Bays and Omega's Seamaster 300s (although still slightly higher) - categorizing itself towards a more "luxurious" prized classification. Therefore, Seiko knew they needed the quintessential 6159 elements within a much more affordable price point for their fans. And yes, Seiko already answered that by launching the Prospex diver duo: the SBDX061 and 63.

"If you missed out on the SLA025, or long for a great example of a vintage Seiko diver but can't part with the five-figure sums often required for the best pieces, the Prospex SPB077(SBDC061) is a must-have." - Wornandwound

The inaugural of two 200m divers is modernly built according to today's standard (for Seiko, it's quite substantive) while slicing several essentials from Seiko's MM300 lineage. Deriving from the 6159 design, just like the rest of the SBDX MM300 variants, the SBDC06X adheres to the vintage aesthetics clothed within ultramodern marvels. First up, the bezels are back with the shimmering lacquered steel material, one in black (061) and one in blue (063). Following up is the case with distinct straight lines of a true Marinemaster: as with the 4 o'clock crown, no logo this time around, in keeping the 6159 nostalgia. Therefore collectors are quick to contend the 200m Baby "Marinemaster," and their livery didn't die off.

Apart from all that "1968 Automatic Diver's Re-interpretation," there's the other "modern" side of things, where we find plenty. Instead of a single block case, Seiko constructed the SBDC06X with a conventional three-piece case. There's a separable screw-down case-back with an O-ring gasket. As a result of the construction, Seiko managed to trim down the case's conspicuous thickness by a whole 2mm from the 15mm of those SBDXs' MM300.

(6R15 caliber within the SBDC061)

And within the case, we got the workhorse 6R15 calibers that are considered a tier right below the 8L35 "GS" caliber, which is befitting for Seiko to intentionally protect the SBDC06X as the Babies of the uber MM300. Underneath its sapphire crystal lies the modern "PROSPEX" dial design, another significant departure from the original variants. They now get the specific handset with a "big arrow" hour hand, with a reverse "lollipop" second hand that is commonly found on those SRP77X Seiko "Turtles."

Intriguingly, after spending some time with the first ultramodern and functional Baby MM200, the SBDC061 and 63 felt quite different from Seiko at first. Both of them seemingly distinguish themselves a little too much from the Marinemaster - not in terms of overall slimmer sizing. The dial and case construction resulted in a totally different wearing experience, which was only accentuated by the "modern" eccentric handset. Yes, I agree that Seiko succeeded in offering a more value proposed contender once again. Still, I strongly feel many others who tried them would decide that the SBD06X series is leaning towards a modern Seiko dive watch that's something else from what they were supposed to be initially. I believe they are befitting to start a whole new category on their own.

(The "Prospex" handset On a special edition of the first generation MM200)

Consequently, this had got me worried quite a little bit, as if our only hope to getting a diver that absorbs most of the original MM300/6159 charm is through getting the real premium deal. But relief came two years later when Seiko decided to do the Baby MM200 right this time with more "retro" charisma through the same "slimmed down" package and several exciting elements. And that happened only at the end of 2020 when Seiko got back with their first "professional" dive watch re-issue game. Through the launch of the Prospex 200m divers ref. 125 and 127, AKA the Baby MM Reduced.

Aesthetic Overview

Now we have gotten to the main show of the article. So let's get into the specifications and features of these re-issues.

  1. 42mm in diameter, 48.8mm lug to lug, 12.5mm thick.
  2. Entirely done in 316L stainless steel material from case to bracelet.
  3. Multi-finished in satin-brushed and high polished, coated in Seiko's proprietary Diashield.
  4. Runs on the 6R35 automatic caliber - 24 jewels, 21,600BPH, power reserve of 70 hours.
  5. Sunburst blue dial on the SBDC127 and a matte black dial on the SBDC125 - both with applied indexes.

(SBDC125 AKA the Baby MM200 "Reduced")

Fantastically executed with the same material as the original MM300 and the vintage variants, these two models encapsulate a more accurate look of the Seiko's marvel in producing the first 300m automatic high-beat diver in the world. Yet, the SBDC12X never fails to ooze refined quality, in keeping with today's market.

TheMM200 Reduced is the new direction that Seiko has been attempting since a couple of years back - producing timepieces that cater more to enthusiasts instead of broader consumers. Starting with the SBDC05X "62MAS" to the first generation Baby MM200 SBDC06X, not forgetting the second generation "62MAS" SBDC10X (SEE REVIEW HERE) and the equally new "Captain Willard" Turtles SBDC109 and 111. Now, the SBDC12X series rides along the same wave - considered a high-end vintage re-issue - reviving the very essence of Seiko's legendary dive watches from the sixties.

(The all-new MM200 duo) (Left: SBDC127, Right: SBDC125)

Considering the second series of "baby" Marinemaster re-issues, the MM200 Reduced ameliorates in case construction. Although simpler than the previous generation, the new MM200s offer more significant throwback aesthetics of the yesteryears. In this case, they are modeled on those elements found in the ref. 6159/6215 case design.

Possessing an exceptional build and finish for the price, the Baby MM200 shines in terms of its finishing, containing full mirror-like polishing known as Zaratsu. The distortion-free polished surfaces can be found on the bevel sides and sloped-bottom, only to be separated by the satin-brushed intricacy, both at the top surface and the case flange. This daringly spectacular polish results in ritzy and sleek exteriors with impressive multi-finishing. It is impossible to find another neo-vintage dive watch within this price range (other than within Seiko itself) with similar case finishing qualities.

This finishing is then protected with a unique hardening process over the case known as the Seiko DiaShield treatment, which is a transparent scratch-resistant coating that allows the MM200 Reduced to be 2-3 times harder than standard 316L stainless steel, which measures 300Hv-700Hv as compared to 200Hv in hardness. As this series is heavily "6159" inspired, the whole case built is elevated with those signature crisp lines flowing throughout the sides, extending to the angled blade-edged lugs.

(Zaibatsu finishing on those sharp lines of the SBDC127)

The multi-piece case construction, redesigned for the occasion, comes in a different size ratio. The mid-case section to be noticeably the largest, and with good reason. Seiko got a lot of details right this time. Like the additional satin-brushed middle section that separates the two mirror-polished beveled surfaces at the top and bottom, it transcends the whole case into a sculpture-like piece of art. This other case satin-brushed sides are the key ingredient to elevate the iconic bold design of the 6159/6215 ethos - that was missing in the previous MM200 SBDC06X. With that said, the elaborated case lines flow seamlessly throughout the case, showcasing an even more precise transition between each finishing and surface.

(The additional satin-brushed side seen on the SBDC127 (top) compared to the previous generation)

Another exemplary aspect would be the development of a new bracelet found on the SBDC12X. As was the case with the third generation 62MAS, much emphasis was placed on executing a worthy metal bracelet as capable as the watch head itself, and the band certainly did not disappoint. Found on both models, the metal bracelet is of solid craftsmanship itself - with the same polishing effort found on the case as can be seen throughout—all that along with a considerable amount of DiaShield protection. From the end-links to the all-new clasp system, the vertical brush strokes on the top surfaces with mirror-finished on the sides are so well done that the bracelet doesn't seem to be mismatched with the gleaming stainless steel case.

(An impressive metal bracelet found on the SBDC127)

(Each link is a solid piece with satin-brushed finishing on top and mirror-polished on sides)

A surprise move by Seiko, on both models, genuinely delivered with equally well-executed metal bracelets, which seem more fitting and of a better overall value proposition than, say, a rubber strap on either one (which can be purchased later on with ease and for less costly. At between the sub $1000 to $1200 price point, Seiko has kept their newer, better releases in check on price point where entry to mid-range mechanical watches usually are, while both the SBDC125 and 127 are anything but. Seiko once again excels with these two watches, and they continue to punch hard in terms of craftsmanship with refinement.

The Upgraded 6R Caliber

Mechanically, the new Baby MM200 is equally upgraded with the new generation of Seiko's workhorse movement. Let's talk about its 6R engine. Launched in 2006, the 6R15 caliber was the proper upgrade from the reliable 7S family. Now done with better finishing and the use of a Spoon 510 mainspring that ensures good power throughout the 50 hours power reserve, the 23 jewels automatic movement beats steadily at 21,600BPH (3 Hertz) with proficiency in better accuracy and chronometry. All that with the inclusion of hand-winding and hacking capabilities.

(The 6R35 caliber)

Proven to be reliable and accurate, Seiko took their time, thirteen years to be exact, leaping one step further in developing the 6R15 engine in 2019. The movement was released as the 6R35 caliber, which is characterized by a longer power reserve of 70 hours and an additional jewel on the main plate (also found on "C" and "D" 6R15 variants). The latest top-of-the-line PROSPEX models that include the dynamic MM200 duo are powered by this new movement, allowing this remarkable re-issued diver to possess the highest modern specifications.

I would like to remind you that the 6R family is probably still the best time-only movement you can get for Seiko's sub-$1000USD category. And the boys behind it even made an effort in upgrading the 6R15 caliber when it already leaps above those from the Europeans' side. Therefore, I continue to believe that the 6R35 movement is Seiko's state-of-the-art engine with proven ruggedness and accuracy for many years of operation - an absolute qualified movement with almost three days of power reserve - and an excellent option to be used in top-tier watches that are ready for some heavy abuse.

"Reduced" With Nostalgia

Seiko's nascent space in updating their Prospex diver's collection since the 62MAS re-issues launched earlier in 2020 had to be the sizing. Adopting sizable dimensions with vintage orientation can be seen as a brilliant move in today's time, even for the SBDC12X. The Marinemaster/6159 case dimension is executed in 42mm in diameter, with a shortened lug to lug distance of 48.8mm. And if you think the Baby MM200 SBDC06X got the slimming pills at 13.1mm, this new generation 12X beats the status quo with another trim of 0.6mm. Thus, the new Baby MM200 earns its "Reduced" sobriquet well. The SBDC125 and 127 notably the most wearable ones out of the rest of "Marinemasters" - a daily fit.

(Reduced in size alright)

"…my personal preference is to balance the essence of a design with real-world wearability." - Rob Nudds, Fratello Magazine

(Finally, a brilliant sizing for the 1968 professional diver re-issue)

Crucial to the appeal of the new Baby MM200 Reduced is everything else being well proportioned. While maximalist to the core, diffusing the exact exuberant energy like those from the sixties, it has just enough wrist presence for enthusiasts with compactness. Taking its cues from the 6159, the dive watch is a spot-on traditionalist in several flavors, exemplified by a subtle contemporary style like the choice of dial colors. Clearly, the latter is also evinced by the use of the 120-click anti-clockwise, rotating steel bezel on the SBDC125 and the brighter 127's sunburst blue dial. Both elements tantalized the mix of nostalgia and modernism.

Like for instance, up close, the sunburst blue dial reveals a contemporary theme with a certain casualness, only to give a tad soberer impression when paired with its classic black 6159 lacquered steel bezel. Together, the sunburst effect of the main dial, paired along with the sheens of the lacquered bezel, the SBDC127 just screams vintage charm with a sprinkle of elegance.

(Steel bezel applied for the first time on a vintage re-issue)

(A usual sunburst dial in an oceanic blue hue)
On the other hand, despite the retro 1960s aura of the monocoque case dive-watch, the inclusion of a stainless steel bezel on top of the SBDC125 brings out the solemnity. First, in a vintage re-issue aspect, the bezel surface is finished in radial brush strokes, save it for the markers in which are filled with black paint for legibility, with the inclusion of the luminous pip at 12 o'clock. Donned together with the no-nonsense matte black dial, the diver stripes down the lineage color to reveal its purest tool watch attributes. It radiates much more purposefully with a monochromatic theme, especially with its matching steel bracelet.

(Full steel baby)

Speaking of the bezel, the MM200 Reduced boasts proper throwback of the originals with the 60-minute markers, with properly spaced-out double-digit numerals at every tenth-minute interval. When rotating the bezel, it operates in a buttery smooth manner without compromising on precision. The slightly-muted click sound at every rotation reminds me of the bezel action found on the MM300s - without the generic metallic clicking noises found on many dive watches. The lacquered black bezel or the monochrome steel bezel complements the glossy frames of the applied hour markers. These markers are kept in almost the same manner as the originals. Still, they are dramatized further at those cardinal points, which can be seen positively. Oh, and an excellent detail led by the Seiko development team was the inclusion of the well-sized Lumibrite hour plot right beside the frameless date aperture, lending a better balance in proportion to the opposite 9'o clock trapezoid marker.

(Monochromatic bezel in full steel)

(The additional applied hour plot beside the date-display)

That marvelous built could be said for the unsigned screw-down crown at 4'o clock. Utilizing the crown can be done so effectively. The adjustment of time and winding to the screwing in-and-out process feels crisp and precise without much fidgeting or hassle.

(Sterile screw-down crown at 4'o clock)

(The handset is true to the original, including the "traffic light" seconds hand)

To further emphasize the throwback elements, Seiko has correctly done it this time by bringing back the original handset of the grand-daddy 6215. Now sans the "PROSPEX" arrowhead hour and the reverse lollipop seconds, the new generation MM200 gives a whiff of the originals with the broad sword hour hand, and of course, the coveted "traffic light" second hand that only its lineage started. The handset is now executed in full metallic-manner without the "ghosting" effect (Matte black to camouflage within the matte black dial) at the stems and legs, resulting in an excellent repository of classic Marinemaster references. And at the same time, the hour and minute hands are executed with details that only to be seen in modern time, as they are done with facets and different finishings. Seiko truly nailed the ideal format of their essential dive watch with the certainty of what makes it appealingly extravagant. With that, let us take a closer look in comparison to their elder sibling, the cult-status SBDX023, to justify how well the new-gen MM200s are executed.


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