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The Clash of the Emperors
An In-Depth Look at the Prospex 1000m Marinemaster Tunas
Published by: Samuel Ng
Published by: Samuel Ng
Nov 04, 2020
Introduction
(The Battle of the Emperors begins)
There have not been many dive watches in the industry that can surpass the charm of the Seiko Tuna which has left an indelible impression on Seiko enthusiasts and hobbyists. This series does not take inspiration from the fish type but from the cylindrical shape of the can that stores the tuna fish. The round diver's case featuring an outer-protector, and a no-lugs design draws close resemblance to the tuna can which the Japanese watchmaker recently acknowledged, finally going along with this nickname.
Seiko releases many unique dive watches throughout the years and the Tuna is at the top of the list. Introduced in 1975, the Tuna collection comes in many variants. Despite strictly retaining its classic tuna can aesthetic, this series does not compromise on functionality both on land and underwater at any point of time. Led by veteran engineer Mr. Ikuo Tokunaga and his team, Seiko’s Tuna collection is testament to their expertise in tackling the challenge to craft dive watches suitable for hardcore underwater use with the rise in demand due to the increase in popularity of saturation.
(The man behind the iconic Tuna) (Photo Credit: TheWatchSite)
Why would Seiko and Mr. Takunaga's team find it compelling to build a watch to handle this niche subaqueous purpose? Well, that may be due to their competitive spirit after receiving a letter from a critic in Kure City, Hiroshima, complaining that their dive watches "just don't make the cut for saturation divers" back in 1968.
However, without Seiko taking a hit like this, I might never have the chance to set my eyes upon these extraordinary dive watches, the latest 2020 releases are coined the Emperor Tunas and they include the SBDX014 and SBDX038. Both models are deemed the pinnacle of Seiko's 50 years of marine engineering and watchmaking. In this article, I will be presenting a comparative review of both models, scrutinising their technical aspects and then delving into the Tuna's lineage to appreciate these desirable, over-built "time beasts" that are the pride of this Japanese brand. Even until today, there's nothing in the watch industry that holds a candle to these timepieces.
A Saturation Dive Watch From The East
(An explosion view of its construction) (Photo Credit: TheSpringBar)
The Tuna collection showcases timepieces that function seamlessly under great depths, for instance, they operate underwater starting at 300m and go through a decompression process when resurfacing. Hence, it is necessary for the Tunas to prevent helium gas from penetrating (or escaping out) into the case and cracking the watch's crystal during the decompression process. With the goal to create a professional dive watch that is not just impermeable but also able to survive harsh pressures underwater, Mr. Takunaga and his team responded to this challenge by tackling it with two ingenious solutions.
(Seiko’s solution for saturation diving)
Within this period, the Swiss watchmakers had already started designing saturation dive watches like the Sea-Dwellers and Ploprofs, where the former uses an additional valve-system at the side of the case to release the helium gas steadily during decompression. In contrast, the latter is crafted with a mono-bloc stainless case, a unique crown and crystal that prevent the gas from entering.
As for Seiko, these Japanese engineers came up with two solutions:
(Yes, it's a Bond’s watch too) (Photo Credit: TheSpringBar)
Now armed with these solutions, the next challenge would be to mould the ideal form that enables maximum functionality which is devised by yet another notable name from Seiko, the one and only Taro Tanaka. He is famous for his "grammar-of-design" that Seiko complied with since the early 1960s and his effort and vision led to the distortion-free, mirror-finished Grand and King Seikos that have revolutionised the watch industry till today. He was also the designer of Seiko's first-ever saturation dive watch. Inspired by his personal folding camera, Mr. Tanaka created a round outer-case to protect the primary round diver, leading to the birth of the iconic tuna can shape.
(The legendary designer of Seiko) (Photo Credit: KingSeiko)
In 1975, Seiko launched a whole new type of dive watch with 23 breath-taking horological novelties that catered to professional use. Now that's what I call rising up to the challenge with real innovations!
The First Tuna Diver
So, you may be wondering how the finalized design turned out in 1975. Well, it is safe to say that it was ground-breaking and the world has gotten its first glimpse of the perfect combination of an exceptional case design and exquisite engineering. This demonstrates Seiko's capability in crafting an over-built watch. Taking the form of a tuna can for the first time, the 6159-7010 (YAQ028) featured a lug-less, double-layered round case with a proprietary Hardlex mineral crystal and an accordion- style polyurethane strap. Due to the materials used and its robust design, Seiko's and the world’s first diver had a professional depth due to its 600m water resistance. This timepiece has a monocoque titanium case topped with a steel bezel, further bolted together with another titanium outer-shroud with a preliminary ceramic coating for better shock resistance.
(The Grandfather Tuna, the first of its kind) (Photo Credit: TheWatchSite)
This resulted in a massive 51mm case without any extended lugs is more wearable than its measurements suggest. The "Grandfather" Tuna 6159-7010 is powered by the Grand Seiko automatic hi-beat caliber 6159 which beats at 36000 bph. Since its inception, the Tuna has set the benchmark and design philosophy for future releases and some of these design elements are still reflected on both the SBDX014 and 038 Emperor Tunas.
The Golden Boy
Three years after the first Tuna, Seiko decided to embrace the quartz technology in its most robust dive watch and decided to incorporate it inside the Ref. 7549-7009 released in 1978. Now, you might be wondering since I am delving into Seiko’s mechanical models, why bring up this quartz Tuna? Well, that is because this particular model is the earliest to flaunt grand "gold" accents, which would later on find their way onto the Emperor Tunas.
(First Golden Tuna) (Photo Credit: FratelloWatches)
Coined as the "Golden Tuna" back then, this Tuna showed off an alluring gold hue which accentuated the inner monocoque casing (inside its black ceramic coated titanium shroud) with gold titanium nitride (TiN), a tough ceramic coating material. Hence, the inner case has the same hardness as its outer ceramic-coated shroud and boasts the same gold-tone steel bezel, screws and crown. Additionally, Ref. 7549-7009 measures 2mm smaller than the first Tuna while maintaining a 600m water resistance. Therefore, this new addition to the Tuna collection qualifies as a professional Tuna with the debut of this luxurious hue.
The 1000m Depth
Another worthy model that alludes to the Emperors would be the Ref. SBDS018 which is the horological offspring of the previous two models with a whopping 1000m water resistance. It took Seiko exactly eight years from 1986 to raise the water pressure rating while retaining the aesthetics of the Golden Tuna. It is also worthy to note that during the 1980s, there weren't many four-digit WR dive watches out there in the market yet.
(The first 1000m water-resistant Tuna) (Photo Credit: Picuki)
The SBDS018 is powered by the established 7C46 high-torque quartz caliber that would later go on to power the 300m Marine Master Tunas in the SBBN series. For around another thirteen years, there was not a single professional Seiko Tuna released until 1999, the 1000m Golden Tuna Re-Issue Ref. SSBS018.
The 8L35 Caliber
The watch, released in 2000, that led to the SBDX014 and subsequently the SBDX038, is the Ref. SBDX005 which pays tribute to the 1975 Grandfather Tuna. Now, this timepiece is powered by a mechanical caliber crafted by Seiko which is one of the best movements produced by this Japanese watchmaker that powers the Emperors while still retaining the historical design elements on the first Tuna (with better materials and finishing).
(The unbadged Grand Seiko movement - 8L35 caliber) (Photo Credit: CaliberCorner)
This marvellous movement is none other than the 8L35 caliber which is one of the top automatic calibers derived from the premium Grand Seiko's 9S55 movement. Showing off an undecorated appearance, the 8L35 is an in-house automatic movement made by the Grand Seiko. It is also known to be as durable as the Rolex's caliber 3135 movement which powers its coveted dive watches. Some even deem the 8L35 as a tad more sophisticated, imagine that!
Aesthetics Overview
(“This watch is a beast”)
Even though I have skipped over a few vintage variants from the Tuna archives, the models mentioned above are the select few that had paved the way for the "Emperors." In addition to that, they have underlined the progress and foundations of Seiko's saturation dive watch development.
"This watch is a beast, a purpose-built tool with no concessions, a watch with a singular objective: being a performing dive watch." - Brice Goulard, Monochrome 2017
(The SBDX014 Emperor Tuna carries the baton in a dressy way)
Conceived to mark the 50th anniversary for the brand's dive watches, the Seiko Prospex Marinemaster 1000m Automatic Ref. SBDX014 (along with its full-black brethren SBDX013) is the epitome of the Tuna standard, flaunting all the unique Tuna hallmarks. For the first time in a rose gold tone, this timepiece is classified as a re-issue that has achieved both the aesthetic and technical flair of the vintage variants.
Its birth was to commemorate Seiko's unwavering determination in creating the most robust dive watch it could make at any given time. Indeed, the Marinemaster 1000m SBDX014 is truly a vintage-inspired dive watch that is dressed up for the occasion.
(Monocoque case designs)
The SBDX014, which had been the only deep diver in a rosy hue, was subsequently superseded by its own with minimal tweaks after five years, the all-new 2020 rose gold Emperor Tuna. One can even say that the SBDX038 is the "Mark II" version of Seiko's 50th-anniversary Tuna. These two models are identical in many ways, but the details reveal their uniqueness. Before I go into their distinctive traits, here are the similarities:
(Celebrating Seiko’s 50th anniversary of dive watchmaking)
As its Tuna nickname implies, the inner-case which surrounds the bezel, movement and dial is made entirely in titanium. Bolted by four Torx screws in rose gold hues, the inner casing is then held by the second layered shroud built in full ceramic, which graces both Tunas with a virtually indestructible form that weighs half the total weight if it had been done in steel. With a diameter of 52mm and thickness of 17mm, this diver exudes a confident, sober feel on the wrist.
First of its kind material-wise, the full ceramic shroud has openings from 12 to 3 o'clock position at the top as well as from 6 to 9 o'clock at the bottom. This would allow the user to adjust the bezel when intended to avoid unintentional adjustments.
(Matching rose gold Torx screws that lock the ceramic shroud)
Once all of these screws are unlocked, the shroud can be individually removed from the top, revealing the rose gold titanium case and steel bezel. This then allows the watchmaker to get to the heart of the timepiece, its mechanical movement, for repair or servicing intervals.
The colour hue on both is chosen deliberately to pay tribute to the Ref. 7549-7009 released in 1978. Instead of a yellow gold-tone, Seiko decided to coat the titanium case, screws, crown, and steel bezel in a rose gold-tone that add a more luxurious warmth as compared to the yellow gold accents. While the 7549 Golden Tuna flaunts a gold tone due to its Titanium nitride (TiN) coating, the rose gold hue on the SBDX014 and 038 appears more decorative than functional.
(Yes, it does looks dressier than ever before)
Colours aside, both Emperor Tunas possess a unique matte black bezel insert with "floating" markers in white. These bezel inserts create a sort of depth while offering maximum legibility.
(“Floating” markers on bezel)
Both models have a flat sapphire crystal instead of Seiko's proprietary Hardlex crystal with an anti-reflective coating applied on the inner surface to enhance readability. What’s more, the AR coatings on both models showcase brownish hues when viewed at different angles under a direct light source that bring out the rose gold case and markers.
(Unique brownish hues on the crystal)
The standard "Marinemaster" Tuna series is usually overly masculine with their colourways, but both Rose Gold Tunas manage to bring their lustre down despite their large dimensions. Instead, this deep rose tone graces the watches with a refreshing bold charm, a visual break from its virile character. While it isn't rare to find a 1000m tool watch in modern horology, many can testify the compelling nature of the Emperor Tuna.
The Accordion design
While the Tuna divers are fitted with several novelties, the polyurethane strap (later in silicon) comes with each one of them tops off their handsome look flawlessly.
(The accordion silicon rubber on the Emperors)
Generally, when it comes to watchmaking, only the metal bracelets or, to a certain extent, the exotic leather bands are mentioned in great detail while the plain plastic or rubber strap are glossed over. However, Seiko's original strap is a worthy contender of the high-grade bracelets and deserves some mention here.
Before launching the first 6159-7010 Tuna in 1975, the Seiko team specifically designed a black strap made of polyurethane material. This strap possesses an intriguing "accordion" pattern at each top side near the attachment to the case. As its name implies, the pattern takes design cues from the bellow of the box-shaped musical instruments.
(Photo Credit: Pinterest)
The main reason for this material choice is that it is pliable and soft while not easily broken or damaged to allow for rugged use. In addition, the folding patterns allow for the expansion and contraction of the strap which is especially useful in accommodating the changes in pressure underwater.
After thirty years, this plastic strap has been replaced with silicon which offers better flexibility and reliability. In comparison, the rubber material is much softer than the already supple feel of the polyurethane strap. This newly upgraded accordion rubber strap makes its first appearance on the Quartz "Darth" Tuna Ref. SBBN025, the SBDX001 (A.K.A MM300) and of course, the Emperor Tunas.
(Folding patterns with unique grooves underneath)
Complementing its colourway, the metal buckle and keepers are done in a matching rose gold hues. The signed keeper is finished with multi-polishing that sits in contrast to the sand-blasted matte tang buckle. Additionally, the iconic Seiko “tsunami” emblem embossed on one side of the strap's end marks Seiko's tradition. Flipping the straps over and you noticed a unique texture that runs uniformly throughout the underneath. The main reason for that is to allow a quick dry process when the diver resurfaces from the ocean.
Grand Seiko Caliber
"...watchmakers assemble the movements of the mechanical Grand Seiko, Credor and some Prospex (those with caliber 8L35) watches. All watches are also cased and tested in this SII building (Morioka)." - Robert-Jan Broer, 2015
(A watchmaker assembling the 8L35 caliber in Morioka facility) (Photo Credit: FratelloWatches)
I could not emphasize the significance of involving a caliber from the 8L automatic family. That is as if to say someone in the upper Grand Seiko decided to permit its finest modern mechanical movement for its more-value-driven brother in Seiko. Sure, you might agree that the workhorse Seiko 6R15 automatic, or even its latest upgraded 6R35, would befit the most avant-garde mechanical dive watch Seiko has ever produced; but the 8L35 caliber is something else.
Seiko’s Prospex and Brightz collections get the privilege to incorporate the "unbadged" G.S. 9S55 caliber known as the 8L35 which is manufactured at the Seiko Instruments Inc (SII) Facility in Morioka. Only the most eminent movements are assembled and fitted into the watch case for this Japanese Maison’s heavyweight watches including the mechanical Credors, Grand Seikos and some "serious" Seiko models from the collections mentioned above including the SBDX Tunas were included.
(The G.S. 9S55 caliber - equivalent to the 8L35) (Photo Credit: GrailWatchReference)
The 8L35 caliber, incorporated in the Seiko Prospex collection, is arguably the most compelling automatic movement that is used in the Marinemaster dive watches. The caliber embodies every trait of the Grand Seiko's first automatic movement since its rebirth in 1998. The caliber employed Seiko's Micro Electro Mechanical Systems (MEMS) technology in the manufacturing process for fabricating precision parts like the escapement. That includes:
(The Battle of the Emperors begins)
There have not been many dive watches in the industry that can surpass the charm of the Seiko Tuna which has left an indelible impression on Seiko enthusiasts and hobbyists. This series does not take inspiration from the fish type but from the cylindrical shape of the can that stores the tuna fish. The round diver's case featuring an outer-protector, and a no-lugs design draws close resemblance to the tuna can which the Japanese watchmaker recently acknowledged, finally going along with this nickname.
Seiko releases many unique dive watches throughout the years and the Tuna is at the top of the list. Introduced in 1975, the Tuna collection comes in many variants. Despite strictly retaining its classic tuna can aesthetic, this series does not compromise on functionality both on land and underwater at any point of time. Led by veteran engineer Mr. Ikuo Tokunaga and his team, Seiko’s Tuna collection is testament to their expertise in tackling the challenge to craft dive watches suitable for hardcore underwater use with the rise in demand due to the increase in popularity of saturation.
(The man behind the iconic Tuna) (Photo Credit: TheWatchSite)
Why would Seiko and Mr. Takunaga's team find it compelling to build a watch to handle this niche subaqueous purpose? Well, that may be due to their competitive spirit after receiving a letter from a critic in Kure City, Hiroshima, complaining that their dive watches "just don't make the cut for saturation divers" back in 1968.
However, without Seiko taking a hit like this, I might never have the chance to set my eyes upon these extraordinary dive watches, the latest 2020 releases are coined the Emperor Tunas and they include the SBDX014 and SBDX038. Both models are deemed the pinnacle of Seiko's 50 years of marine engineering and watchmaking. In this article, I will be presenting a comparative review of both models, scrutinising their technical aspects and then delving into the Tuna's lineage to appreciate these desirable, over-built "time beasts" that are the pride of this Japanese brand. Even until today, there's nothing in the watch industry that holds a candle to these timepieces.
A Saturation Dive Watch From The East
(An explosion view of its construction) (Photo Credit: TheSpringBar)
The Tuna collection showcases timepieces that function seamlessly under great depths, for instance, they operate underwater starting at 300m and go through a decompression process when resurfacing. Hence, it is necessary for the Tunas to prevent helium gas from penetrating (or escaping out) into the case and cracking the watch's crystal during the decompression process. With the goal to create a professional dive watch that is not just impermeable but also able to survive harsh pressures underwater, Mr. Takunaga and his team responded to this challenge by tackling it with two ingenious solutions.
(Seiko’s solution for saturation diving)
Within this period, the Swiss watchmakers had already started designing saturation dive watches like the Sea-Dwellers and Ploprofs, where the former uses an additional valve-system at the side of the case to release the helium gas steadily during decompression. In contrast, the latter is crafted with a mono-bloc stainless case, a unique crown and crystal that prevent the gas from entering.
As for Seiko, these Japanese engineers came up with two solutions:
- The implementation of an L-shaped gasket ring that sits in between the crystal and case innovated by Mr. Tokunaga
- A one-piece case that is made with titanium material (rare in those days), instead of stainless steel.
- The use of an L-profiled gasket allows for a tight fit of the glass to the dial, which suppresses the penetration of helium gas to around 1/1000 of a conventional watch, thus forgoing the need for a helium escape valve. The titanium material also enhances corrosion resistance while imbuing intensity and lightness.
(Yes, it's a Bond’s watch too) (Photo Credit: TheSpringBar)
Now armed with these solutions, the next challenge would be to mould the ideal form that enables maximum functionality which is devised by yet another notable name from Seiko, the one and only Taro Tanaka. He is famous for his "grammar-of-design" that Seiko complied with since the early 1960s and his effort and vision led to the distortion-free, mirror-finished Grand and King Seikos that have revolutionised the watch industry till today. He was also the designer of Seiko's first-ever saturation dive watch. Inspired by his personal folding camera, Mr. Tanaka created a round outer-case to protect the primary round diver, leading to the birth of the iconic tuna can shape.
(The legendary designer of Seiko) (Photo Credit: KingSeiko)
In 1975, Seiko launched a whole new type of dive watch with 23 breath-taking horological novelties that catered to professional use. Now that's what I call rising up to the challenge with real innovations!
The First Tuna Diver
So, you may be wondering how the finalized design turned out in 1975. Well, it is safe to say that it was ground-breaking and the world has gotten its first glimpse of the perfect combination of an exceptional case design and exquisite engineering. This demonstrates Seiko's capability in crafting an over-built watch. Taking the form of a tuna can for the first time, the 6159-7010 (YAQ028) featured a lug-less, double-layered round case with a proprietary Hardlex mineral crystal and an accordion- style polyurethane strap. Due to the materials used and its robust design, Seiko's and the world’s first diver had a professional depth due to its 600m water resistance. This timepiece has a monocoque titanium case topped with a steel bezel, further bolted together with another titanium outer-shroud with a preliminary ceramic coating for better shock resistance.
(The Grandfather Tuna, the first of its kind) (Photo Credit: TheWatchSite)
This resulted in a massive 51mm case without any extended lugs is more wearable than its measurements suggest. The "Grandfather" Tuna 6159-7010 is powered by the Grand Seiko automatic hi-beat caliber 6159 which beats at 36000 bph. Since its inception, the Tuna has set the benchmark and design philosophy for future releases and some of these design elements are still reflected on both the SBDX014 and 038 Emperor Tunas.
The Golden Boy
Three years after the first Tuna, Seiko decided to embrace the quartz technology in its most robust dive watch and decided to incorporate it inside the Ref. 7549-7009 released in 1978. Now, you might be wondering since I am delving into Seiko’s mechanical models, why bring up this quartz Tuna? Well, that is because this particular model is the earliest to flaunt grand "gold" accents, which would later on find their way onto the Emperor Tunas.
(First Golden Tuna) (Photo Credit: FratelloWatches)
Coined as the "Golden Tuna" back then, this Tuna showed off an alluring gold hue which accentuated the inner monocoque casing (inside its black ceramic coated titanium shroud) with gold titanium nitride (TiN), a tough ceramic coating material. Hence, the inner case has the same hardness as its outer ceramic-coated shroud and boasts the same gold-tone steel bezel, screws and crown. Additionally, Ref. 7549-7009 measures 2mm smaller than the first Tuna while maintaining a 600m water resistance. Therefore, this new addition to the Tuna collection qualifies as a professional Tuna with the debut of this luxurious hue.
The 1000m Depth
Another worthy model that alludes to the Emperors would be the Ref. SBDS018 which is the horological offspring of the previous two models with a whopping 1000m water resistance. It took Seiko exactly eight years from 1986 to raise the water pressure rating while retaining the aesthetics of the Golden Tuna. It is also worthy to note that during the 1980s, there weren't many four-digit WR dive watches out there in the market yet.
(The first 1000m water-resistant Tuna) (Photo Credit: Picuki)
The SBDS018 is powered by the established 7C46 high-torque quartz caliber that would later go on to power the 300m Marine Master Tunas in the SBBN series. For around another thirteen years, there was not a single professional Seiko Tuna released until 1999, the 1000m Golden Tuna Re-Issue Ref. SSBS018.
The 8L35 Caliber
The watch, released in 2000, that led to the SBDX014 and subsequently the SBDX038, is the Ref. SBDX005 which pays tribute to the 1975 Grandfather Tuna. Now, this timepiece is powered by a mechanical caliber crafted by Seiko which is one of the best movements produced by this Japanese watchmaker that powers the Emperors while still retaining the historical design elements on the first Tuna (with better materials and finishing).
(The unbadged Grand Seiko movement - 8L35 caliber) (Photo Credit: CaliberCorner)
This marvellous movement is none other than the 8L35 caliber which is one of the top automatic calibers derived from the premium Grand Seiko's 9S55 movement. Showing off an undecorated appearance, the 8L35 is an in-house automatic movement made by the Grand Seiko. It is also known to be as durable as the Rolex's caliber 3135 movement which powers its coveted dive watches. Some even deem the 8L35 as a tad more sophisticated, imagine that!
Aesthetics Overview
(“This watch is a beast”)
Even though I have skipped over a few vintage variants from the Tuna archives, the models mentioned above are the select few that had paved the way for the "Emperors." In addition to that, they have underlined the progress and foundations of Seiko's saturation dive watch development.
"This watch is a beast, a purpose-built tool with no concessions, a watch with a singular objective: being a performing dive watch." - Brice Goulard, Monochrome 2017
(The SBDX014 Emperor Tuna carries the baton in a dressy way)
Conceived to mark the 50th anniversary for the brand's dive watches, the Seiko Prospex Marinemaster 1000m Automatic Ref. SBDX014 (along with its full-black brethren SBDX013) is the epitome of the Tuna standard, flaunting all the unique Tuna hallmarks. For the first time in a rose gold tone, this timepiece is classified as a re-issue that has achieved both the aesthetic and technical flair of the vintage variants.
Its birth was to commemorate Seiko's unwavering determination in creating the most robust dive watch it could make at any given time. Indeed, the Marinemaster 1000m SBDX014 is truly a vintage-inspired dive watch that is dressed up for the occasion.
(Monocoque case designs)
The SBDX014, which had been the only deep diver in a rosy hue, was subsequently superseded by its own with minimal tweaks after five years, the all-new 2020 rose gold Emperor Tuna. One can even say that the SBDX038 is the "Mark II" version of Seiko's 50th-anniversary Tuna. These two models are identical in many ways, but the details reveal their uniqueness. Before I go into their distinctive traits, here are the similarities:
- 52mm in diameter, 53mm lug to lug (41mm hidden lugs beneath) and 17mm thickness.
- Matte black dial to provide perfect contrast and removal of any reflection.
- Full titanium monocoque case with a sandblasted ceramic outer shroud.
- 1000m water resistance with rose-gold steel bezel.
- Fitted with signature black accordion silicon strap in matching rose gold hardware.
- Runs on the 8L35 automatic caliber - 26 jewels, 28,800 bph, power reserve of 50 hours.
(Celebrating Seiko’s 50th anniversary of dive watchmaking)
As its Tuna nickname implies, the inner-case which surrounds the bezel, movement and dial is made entirely in titanium. Bolted by four Torx screws in rose gold hues, the inner casing is then held by the second layered shroud built in full ceramic, which graces both Tunas with a virtually indestructible form that weighs half the total weight if it had been done in steel. With a diameter of 52mm and thickness of 17mm, this diver exudes a confident, sober feel on the wrist.
First of its kind material-wise, the full ceramic shroud has openings from 12 to 3 o'clock position at the top as well as from 6 to 9 o'clock at the bottom. This would allow the user to adjust the bezel when intended to avoid unintentional adjustments.
(Matching rose gold Torx screws that lock the ceramic shroud)
Once all of these screws are unlocked, the shroud can be individually removed from the top, revealing the rose gold titanium case and steel bezel. This then allows the watchmaker to get to the heart of the timepiece, its mechanical movement, for repair or servicing intervals.
The colour hue on both is chosen deliberately to pay tribute to the Ref. 7549-7009 released in 1978. Instead of a yellow gold-tone, Seiko decided to coat the titanium case, screws, crown, and steel bezel in a rose gold-tone that add a more luxurious warmth as compared to the yellow gold accents. While the 7549 Golden Tuna flaunts a gold tone due to its Titanium nitride (TiN) coating, the rose gold hue on the SBDX014 and 038 appears more decorative than functional.
(Yes, it does looks dressier than ever before)
Colours aside, both Emperor Tunas possess a unique matte black bezel insert with "floating" markers in white. These bezel inserts create a sort of depth while offering maximum legibility.
(“Floating” markers on bezel)
Both models have a flat sapphire crystal instead of Seiko's proprietary Hardlex crystal with an anti-reflective coating applied on the inner surface to enhance readability. What’s more, the AR coatings on both models showcase brownish hues when viewed at different angles under a direct light source that bring out the rose gold case and markers.
(Unique brownish hues on the crystal)
The standard "Marinemaster" Tuna series is usually overly masculine with their colourways, but both Rose Gold Tunas manage to bring their lustre down despite their large dimensions. Instead, this deep rose tone graces the watches with a refreshing bold charm, a visual break from its virile character. While it isn't rare to find a 1000m tool watch in modern horology, many can testify the compelling nature of the Emperor Tuna.
The Accordion design
While the Tuna divers are fitted with several novelties, the polyurethane strap (later in silicon) comes with each one of them tops off their handsome look flawlessly.
(The accordion silicon rubber on the Emperors)
Generally, when it comes to watchmaking, only the metal bracelets or, to a certain extent, the exotic leather bands are mentioned in great detail while the plain plastic or rubber strap are glossed over. However, Seiko's original strap is a worthy contender of the high-grade bracelets and deserves some mention here.
Before launching the first 6159-7010 Tuna in 1975, the Seiko team specifically designed a black strap made of polyurethane material. This strap possesses an intriguing "accordion" pattern at each top side near the attachment to the case. As its name implies, the pattern takes design cues from the bellow of the box-shaped musical instruments.
(Photo Credit: Pinterest)
The main reason for this material choice is that it is pliable and soft while not easily broken or damaged to allow for rugged use. In addition, the folding patterns allow for the expansion and contraction of the strap which is especially useful in accommodating the changes in pressure underwater.
After thirty years, this plastic strap has been replaced with silicon which offers better flexibility and reliability. In comparison, the rubber material is much softer than the already supple feel of the polyurethane strap. This newly upgraded accordion rubber strap makes its first appearance on the Quartz "Darth" Tuna Ref. SBBN025, the SBDX001 (A.K.A MM300) and of course, the Emperor Tunas.
(Folding patterns with unique grooves underneath)
Complementing its colourway, the metal buckle and keepers are done in a matching rose gold hues. The signed keeper is finished with multi-polishing that sits in contrast to the sand-blasted matte tang buckle. Additionally, the iconic Seiko “tsunami” emblem embossed on one side of the strap's end marks Seiko's tradition. Flipping the straps over and you noticed a unique texture that runs uniformly throughout the underneath. The main reason for that is to allow a quick dry process when the diver resurfaces from the ocean.
Grand Seiko Caliber
"...watchmakers assemble the movements of the mechanical Grand Seiko, Credor and some Prospex (those with caliber 8L35) watches. All watches are also cased and tested in this SII building (Morioka)." - Robert-Jan Broer, 2015
(A watchmaker assembling the 8L35 caliber in Morioka facility) (Photo Credit: FratelloWatches)
I could not emphasize the significance of involving a caliber from the 8L automatic family. That is as if to say someone in the upper Grand Seiko decided to permit its finest modern mechanical movement for its more-value-driven brother in Seiko. Sure, you might agree that the workhorse Seiko 6R15 automatic, or even its latest upgraded 6R35, would befit the most avant-garde mechanical dive watch Seiko has ever produced; but the 8L35 caliber is something else.
Seiko’s Prospex and Brightz collections get the privilege to incorporate the "unbadged" G.S. 9S55 caliber known as the 8L35 which is manufactured at the Seiko Instruments Inc (SII) Facility in Morioka. Only the most eminent movements are assembled and fitted into the watch case for this Japanese Maison’s heavyweight watches including the mechanical Credors, Grand Seikos and some "serious" Seiko models from the collections mentioned above including the SBDX Tunas were included.
(The G.S. 9S55 caliber - equivalent to the 8L35) (Photo Credit: GrailWatchReference)
The 8L35 caliber, incorporated in the Seiko Prospex collection, is arguably the most compelling automatic movement that is used in the Marinemaster dive watches. The caliber embodies every trait of the Grand Seiko's first automatic movement since its rebirth in 1998. The caliber employed Seiko's Micro Electro Mechanical Systems (MEMS) technology in the manufacturing process for fabricating precision parts like the escapement. That includes:
- A "Spron" (cobalt-nickel alloy) hairspring that enables excellent, durable elasticity for "breathing", resistance to corrosion and high temperature.
- An escape wheel that is 5% lighter than most steel counterparts which allows for lesser power drain.
- A 25% lighter pallet fork due to Seiko's raw material.
- Reinforced mainspring for better consistency in power reserve.
Although the 8L35 movement is impressive with these sophisticated core components, it lacks the hand calibration that the 9S55 is built with. Instead of the finely adjusted hairspring that allows the 9S55 caliber to beat the Swiss chronometer accuracy of -4/+6, the unadjusted 8L35 caliber has a -10/+15 accuracy. Thus, its accuracy and water resistance are the best within Seiko’s collection of mechanical watches while still maintaining the stringent quality control from Morioka's masters. Crafted by Grand Seiko which makes it worthy of the horological spotlight, this movement has also been examined rigorously to ensure it adheres to strict standards.
With 26 jewels and a 50-hour power reserve, this movement operates steadily at 28,800 bph (4 Hertz) and features Seiko's ingenious bi-directional winding "Magic Lever" mechanism that enhances winding efficiency as well as the signature Seiko font date display. However, due to the encasement of the 8L35 caliber within a sealed case-back (if there's even one), one might instead find the finishing on the “unbadged” movement to be well "decorated", perfectly in line with the Grand Seiko effort.
(The finishing and execution are still in G.S. league) (Photo Credit: WatchProsite)
The refined finishing on the 8L35 caliber is evident when I compared this movement with the 6R15 caliber found in top range Prospex models. The "Morioka" stripes on the 8L35 are definitely more pronounced and intricate as compared to the decent industrial finishing found on the 6R15. This is because the 8L35 is finished in the Grand Seiko studio which makes the bridges and rotor shimmer captivatingly with a unique rainbow-effect.
Moreover, the 8L35 does not bear the visual depth of the G.S. 9S55 movement due to the unadjusted regulation and unparalleled execution in finishing that sets it apart from the prestigious Grand Seiko caliber. In spite of this, the 8L35 remains attractive and is used in Seiko's most highly-constructed watches. Hence, through the sharing of movements, the distinctly disparate yet inevitably intertwined connection between Seiko and Grand Seiko is reinforced.
Same But Not Quite
(The two Emperors of the ocean)
However, all that has been mentioned above are atypical to both the SBDX014 and 038. This section will highlight the dissimilarities between both Emperors, namely cosmetic changes and durability upgrades. It is interesting to note that after the SBDX014’s release, it took another five years for Seiko to reintroduce the Emperor Tuna.
"Ever-Brilliant Steel" Treatment
(A new scratch-resistant coating on the bezel)
Moving on to their exterior differences and the first would be the additional in-house scratch-resistant coating on the SBDX038 bezel. Known as "Ever-Brilliant Steel," the rose gold bezel, which is the only exposed part of the watch that is left unprotected, comes with this special coating. This coating was introduced in 2020 and boasts an additional pitting resistance equivalent number (PREN) of 1.7 times that of 316L stainless steel.
Aesthetic Differences 
(New font colours and styling)
(The crowns are different)
Because the "Prospex" signature now shifted to the 6 o'clock position on the dial, the rose gold crown is now sterile on the new SBDX038, gracing it with a neat and clean look.
(Even the caliber texts on the SBDX038 differ from that of the SBDX014)
Moving onto the dial, you can see a significant shift between the two, where the newer SBDX038 omits any embellishment, exuding an intoxicating retro charm. Additionally, the rose gold accents on the SBDX014 found on its flagship "Prospex" handset, rehaut markers and "Marinemaster" texts at the bottom are removed such that the rosy accent on the "Japan, 8L35 - 0000 R 2" text at the bottom is changed to a stark white. What’s more, the nostalgic "Golden Tuna's" handset is done in a matte white instead and finished expertly with a no-frills look. All of the hands retain their traditional style, especially the second hand which pays tribute to the Grandfather Tuna on which the luminous lollipop is reversed nearer to the tip, with the pointer of the second hand piercing through it.
(The SBDX014’s Prospex handset)
Furthermore, the painted "X" and "Automatic, Professional 1000m" texts at the bottom in white complements the "Seiko" logo at the top. The placement of the Prospex X logo on the dial is Seiko’s way of showing its earnestness to collate and tidy up its collection. Now, all the other Marinemasters and Professional tool watches feature the same emblem on their dial, which may not sit well with everyone but is still ultimately deemed to be the right decision.
(OG Tuna handset found on the new SBDX038)
Staying true to its Tuna roots, the new SBDX038 features a frameless date display at the usual 3 o'clock position in place of the quirky half past four position on the SBDX014. This is to further elevate Seiko's design on the newer SBDX038 than the previous iteration launched five years back.
(The off-the-beat date at 4.30 on the SBDX014)
Finally, the last notable element that concludes this aesthetic upgrade would be the vintage hour plots on the SBDX038 that hark back to the Tunas released before 2013. The marker plots are round except for the 3 o'clock marker and the 12 o'clock inverse triangle. Moreover, the round markers on the new Emperor Tuna are deemed "maxi" as they are accentuated with signature white trims around each hour plot, making them seem much more extensive than any variants in the past. This bestows the timepiece with an austere aesthetic while still harking back to its heritage.
Impeccable Builts
It is amazing how both Emperors are on par in execution and finishing, so much so that neither one has an edge over the other. They are designed flawlessly to be Seiko's "ultimate" deep diver with an iconic design.
(Sitting on the throne as Seiko’s ultimate diver)
Although the newest SBDX038 Marinemaster 1000m is reminiscent of its predecessor a few
differences stand out, evoking a sense of authentic nostalgia. The SBDX014 set the standard for an exquisite rose gold 1000m dive watch that paved the way for the SBDX038 launched in 2020. Each timepiece retained some original aspects of their predecessor, the SBDX014 is unfettered and the SBDX038 features a traditional Tuna look. However, despite the sober look of the new SBDX038, this watch hardly flies under the radar and flaunts its deserved Emperor Tuna status.
Cutting Edge Within A Fish Can
The inspiration of both Rose Gold Emperors has clearly rooted in the 1970s Tunas. Its attractive retro vibe, beefy dimensions, but forgivably so for they'd felt as Seiko's obsession in demonstrating its horology, building the highest-specs instrument. Although the brand can be misinterpreted on the focus of affordable, entry watches, the Presage and Prospex lines, notably the Marinemaster series that includes the professional 600m and 1000m Tuna divers, showcases Seiko's competency at a much higher level.
(A Tuna will always be one)
For the past two to three years, Seiko has been restructuring its collection with the redesigned Seiko 5 Sports as well as the new 62MAS and LX collections. These designs have clearly shown that the brand is taking steps forward in re-mastering its timepieces released in the past (not including Seiko’s limited edition re-makes). However, this might not be the case for both the SBDX014 and 038 because they showcase Seiko’s slavish obsession to prolong the Tuna series by increasing the longevity of these 1000m Tuna divers’ designs and cutting edge development while still preserving aesthetic similarities without the fragility of the older models.
As the “Tuna” sobriquet implies, the Emperor Tunas are meant to be the ultimate dive watch at the very top of the professional mechanical tool watch line with their innovative built using cutting edge materials. The finishing on these divers is simply impeccable and despite their big size, they wear comfortably on the wrist!
Go Big Or Go Home
With the "lug-less" design, these dive watches offer a better and more comfortable fit as compared to their 1000m competitors. Furthermore, its full-black brethren (SBDX013) was even tested by Seiko on 6th September 2014. It was strapped on a vessel named "Kaiko 7000II" and was able to reach 4299m before the 8L35 caliber stopped operating and without any signs of leakage. That is more than quadruple the actual water resistance of an Emperor Tuna!
Moreover, its ritzy colour tone is a deep-diving instrument reference that only a handful of watchmakers would dare to take the risk to choose on their most compelling sports watches. Now, if you search for "gold-tone 1000m meter dive watch" (bronze is excluded) on the internet, you will be amazed at how one single collection from Seiko saturates the results page, and that is the Prospex Tunas. The choice of colour is no accident because I believe that the SBDX014 is Seiko’s celebratory timepiece, honouring more than fifty years of fabricating impressive mechanics and materials in a form that surpasses its contemporaries.
(Photo Credit: WatchesbySJX)
The test that Seiko’s Tuna excelled in 2014, monitored from the deep sea research vessel Kairei. The newer SBDX038 retains all the beloved elements from past models such as the beautifully executed and designed movement as well as the antique yet technical aesthetic. This vintage approach makes the Emperor Tunas stand out amongst the many Japanese watch releases in the last few decades with subtle upgrades from time to time.
Best known for its robust watches, the 1000m Marinemaster Tuna selection still offers within the Seiko price range despite being easily worth $2600USD to $3600USD and sticks to an affordable price as compared to the 200m Prospex dive watches which are around $1000USD.
For a reasonable price, you can get a taste of Seiko's most successful line of dive watches with captivating heritage charm and a highly engineered movement with a handsome design. Overall, the Emperor Tunas are, without a doubt, exceptional over-built spectacles within Haute-horology.
Seiko has made its name with its Tuna divers which are extremely high-quality dive watches especially in terms of functionality and durability. There is no doubt that this line has made waves in the dive watch industry as it offers better value for money as compared to its competitors with the same philosophy that can easily cost two to three-fold more.
Final Thoughts
Crowned the Emperors of deep-diving, these two dive watches are magnificent pieces that have been horological icons for fifty years and counting. Since then, Seiko has never lost its know-how with its seamless watch executions, expertly combining innovative materials and modern engineering with traditional watchmaking. The aesthetics and philosophy of these timepieces are reminiscent of the 1975 releases and each exudes an impeccable wrist presence.
After taking both divers along for some adventures at the beach and around the city, I personally feel that in contrast to some critics' opinions, the SBDX014 does not feel like an old primeval clock on the wrist at all. Conversely, it looks as if the latest Tesla X was just released yesterday. Besides, I can vouch that the new SBDX038 offers a wonderful wearing experience and allows for maximum comfort in style.
(They are still wearable even on a small wrist like mine)
Both Emperors occupy the entire 6'3 inches on my wrist. However, I do not feel that it is disproportionate or unwearable (you may have seen a lot of my wrist time on our Instagram). Hence, even though these divers are not meant to be tuxedo or dress pairing pieces, they still grace your wrist with a modern look and a purposeful feel that is ready for action at any time.
Bold and glamorous, the rose gold tones make the Emperors very appealing within the watch industry. Both the discontinued (SBDX014) and replacement (SBDX038) models are unquestionably vintage reissues. They are variations of existing models but are still distinctively attractive in their own way. They are also testament to Seiko's innovation that pushes the boundaries of the brand's ultimate dive watch. Both Tunas are invigorating not only in their sizing, but also its tuna can structure bestows the watches with a sturdy feel with no-frills that deem it the perfect diving companion.
Conclusion
Throughout the five years of the SBDX014’s lifespan, Seiko has taken considerable pleasure in starting a daring "deluxe" take on this dive watch with minor upgrades which are so subtle that I had to scrutinise carefully before I managed to identify them. In spite of that, I still respect Seiko's decision to include these changes as they draw a connection between the old school "gold" Tuna horology and the brand's avant-garde dive watch, the SBDX038.
(Double up on the Rose Gold Emperors)
Till date, the Seiko Emperor Tunas SBDX014 and SBDX038 continue to influence the dive watch landscape. They are also revered, more so than the other models in the Prospex collection, for their ground-breaking use of titanium and ceramic materials and their phenomenal tuna can aesthetic. Additionally, I have no doubt that their glamorous golden hue, fitting for Emperors, is what draws the public’s attention and sets them apart in the saturated watch market. Their expensive look conceals their functionality as a professional dive watch, deeming each Emperor Tuna a fantastic offering by Seiko. With whimsical aesthetics and the employment of unparalleled watchmaking techniques, both timepieces are iconic in their own way.
