If you are a fan of Seiko watches, you probably already know some of the famous nicknames that are used to describe the models that are extremely popular.

Seiko's habit of labeling its watches with nothing more than a reference number undoubtedly led to the spread of these nicknames online and among enthusiasts, especially when the brand appeared to be less media-savvy than it is now.

While names like Cocktail Time and Alpinist come from the brand itself, there are still a lot of popular models out there with names that came from the Seiko community, and not the company that makes these amazing watches.


seiko cocktail and alpinist

Two rare watches that were named by Seiko themselves and not the community - the Cocktail Time (left) and the Alpinist (right) (Source: Seiko Watches and Carat & Co.)


If you want to know more about the history behind the nicknames given to some of the most iconic Seiko models – you are in the right place.  Some of these models and nicknames are better known than others, but all of them should be on your radar as a Seiko fan.

Seiko's diver watches have won a cult following, partly due to their incredible value, and also due to the fact that Seiko has always offered great designs.

Both divers and or collectors, these fans deeply identify themselves to the brand. Many people become so close to the design process that they end up wanting to create their own Seikos!

Seiko has produced tens of thousands of different watch models over the years, and the most collectible Seiko models have garnered unofficial nicknames.


Seiko Watches Prospex Line

Check any series in their catalogue and you'll be met with product code upon product code. (Source: Seiko Watches)


This is going to happen with any loyal fan-base – nicknaming is a sure sign that a specific reference has gained cult status within the community.

The fact that Seiko watches have so many unofficial nicknames reflects the Japanese brand's popularity and cultural influence. No other brand has received such an honor besides Rolex, also bestowed by an adoring global following.

So, if you've ever been curious about the Tuna or Sumo, or some other bizarre but entertaining Nickname, here is a rundown of the most popular divers from Seiko!


Seiko Monster - Look at Those Fangs

The Seiko Monster has been around in one form or another for going on 20 years and features dozens of special editions and colorways. Its ‘monster’ name is said to relate to the dial itself, appearing to be lined with sharp teeth.


Seiko Monster SRP307K1

Caution when putting it on, this Monster looks ready to bite! (Source: Chrono24)


In terms of ‘monsterly’ design, the first and third generations are more traditional, while the second generation goes all in on the aggressive style.

The Seiko SKX779 and SKX789 (aka Monsters) were introduced in 2000 as an extension of their SKX diving watch line.

They quickly became extremely popular with those looking for a low-cost tool watch. With its distinctive appearance - a toothy bezel, huge indices with intense lume, and a bezel guard – as well as bold styling and sturdy build quality, this watch was quickly dubbed the "Monster" by Seiko fans.

The Seiko Monster is one of the biggest and boldest products in Seiko’s lineup, with its huge hands and indexes (as well as the MONSTER lume). It also features chunky steel construction and an aggressive appearance which has made it extremely desirable.


Orange Seiko Monster

The Monster is a menacing watch, but wears really good on large wrists (Source: @portalsatova on IG)


Much like the Seiko Tuna, the Monster's stubby lugs allow it to fit easily on smaller wrists.

The complete Monster series, now in its third generation, is undeniably popular. There is even a Seiko 5 offshoot of the Monster that retains many styling details of the original, and many call the Seiko 5 version the Baby Monster.


Seiko Samurai - Carrying the Spirit of Japan

The original Seiko Samurai was released in 2004 and produced until 2008. According to many people, it obtained its nickname by enthusiasts because of the Samurai sword-shaped hands on the original.


seiko samurai jdm titanium 2004

When you check the time on a Samurai, it is always sharp. Okay, not really. (Source: Wristocracy)


The model has returned to production, and is also offered in special editions from time to time.

Samurais were originally released in steel, but a later titanium version (Ref. SBDA003) became extremely popular. It featured Seiko's 7S35 movement and was seen as a tough diver watch before production ceased.

The Samurai, which in regards to price fell between the SKX and the more expensive variants, was originally a Japan-only release. It had an angular case design and was water resistant to 200 meters, although it still employed the entry-level 7S26 and 7S36 movements.

The bright orange dial edition is the coolest version to get (if you can find one).


orange seiko samurai

The design aesthetic of the Samurai itself is eye-catching, but the bright orange dial makes it more so. (Source: @andrwlm on IG)


Even Seiko's designers are somehow puzzled as to why this specific model is known as the "Samurai." Perhaps this particular series evokes a sense of Japanese design in the eyes of the international community.

With the passage of time, its popularity grew, and the Seiko Samurai became one of Seiko's most wanted dive watches.


seiko prospex samurai srpb51k1

The modern Seiko Samurai SRPB51K1 (Source: @lordhorologist on IG)


The modern Samurai is offered in the Prospex line, and now sports a 4R35 movement that both hacks and handwinds. Unlike many Seiko divers, the Samurai never really found much support in the aftermarket Seiko mod community, although many of our parts fit the movement. SRP Turtle bezels are also cross-compatible with the Seiko Samurai. More details here.

We also have a Samurai case and Samurai bracelet, which many Seiko modders like. Have a look at these great products, and think about what you could do with them on your next Seiko mod.


Seiko Sumo - Dosukoi!*

*a sumo exclamation

There are a few theories about where the nickname of this watch came from.

The first is the case's large size in comparison to the 20mm band. Another reason is that the marking at 12 o'clock mimics the 'Mawashi,' the Japanese sumo wrestlers' underpants during a match.

In any case, the Sumo is a heavy-duty dive watch, weighing 170 grams and measuring 44mm in diameter, making it unsuitable for those with narrow wrists.


seiko sumo

It's one of the chonkiest watches there is in the Seiko Line-up. (Source: @bigblock94300 on IG)


Seiko Sumo was first released in 2007, with three models, the SBDC003 (blue dial with metal bracelet), the SBDC001 (black dial with metal bracelet), and the SBDC005 (orange dial with rubber strap).

The modern version of the watch has an aluminum bezel and is powered by the Caliber 6R35 movement, which has a 70-hour power reserve and is anti-magnetic thanks to the use of Seiko's unique Spron alloy mainspring.

The Seiko Sumo distinguishes itself in a few ways. It has a different bezel than most Seiko divers, with bigger numerals all the way around. Its hands are also far simpler than many of the other Divers watches from Seiko.


seiko sumo green

Bezel insert markings that you can read from 2 arms length away. (Source: @enokidad on IG)


Compared to a diver like the Samurai, the Sumo is more curvaceous and has a totally different feel.

The Sumo, and its blue colored version (creatively named the Blumo) are definitely high-up on the list of coveted dive watches for Seiko fans. Often mentioned in the same breath as the Samurai, the Sumo is one of the highest-quality divers you can get in the $500 to $1,000 range.


seiko blumo

The Seiko "Blumo". We wonder who first thought of the nickname? (Source: Two Broke Watch Snobs)


The Sumo is unquestionably among Seiko's most sought after diving watches. Much like the Samurai, the Sumo has little support in terms of aftermarket parts. It is relatively expensive in the Seiko line, which may be one of the reasons why Seiko modders are less likely to take them apart.


Seiko Tuna / Tuna Can

In 1968, a professional diver wrote to Seiko stating that most diving timepieces couldn't stand up to the rigors of saturation diving.

It took Seiko engineers seven years to release a new model, and in 1975 the Seiko Marine Master Professional, widely regarded as the most extreme diving watch ever made, hit the markets. This Tuna  is the predecessor to the entire Tuna design motif, and is also known as the “Grandfather Tuna”.

Nothing else like it existed back in 1975 — it featured a monocoque titanium case with a unique L-shaped gasket that made the watch immune to helium gas, an accordion-style rubber band, and a protective outer shell that gave it that distinctive tuna-can look.


seiko tuna can

We shared a meme about it last year. (Source: namokiMODS FB)


The Tuna nickname was given by watch collectors, and it stuck. Tuna comes from the phrase "tuna can," which refers to the large cylindrical shrouded-case form which gives the weighty item the appearance of a can of tuna strapped to your wrist.

The Seiko Tuna is by far the largest of the Seiko divers, measuring 48mm in diameter. However, the huge 'lugless' shrouded diver watch has taken in a lot of people who enjoy watches in the 40-42mm range. With its lugs tucked under the case, it is actually easy to wear.


seiko tuna 1968

The shroud is the biggest contributor to the Seiko Tuna's thickness. (Source: Monochrome Watches)


Although there are a few higher-end variants with automatic movements, quartz movements are found in the majority of Tuna models.

The Seiko Tuna series is also extremely accurate and has a low failure rate, key to those who actually use it for saturation diving.

There are several more variations of the Tuna nickname in the Seiko line: the Baby Tuna (SRP637), Emperor Tuna (SBDX011), and Darth Tuna (SBBN013) are famous examples.

Seiko has also opted to use the Tuna design on hybrid analogue-digital models, like the H558-5000, which was introduced in 1982, and made it into the movies on the wrist of Arnold Schwarzenegger. This model was reissued recently (SNJ025), and it still has the classic Tuna shroud!


Seiko Turtle - Adorable and Collectible


The Seiko 6309 was released in 1977 to complement Seiko's existing divers watch range. This watch, with its cushion case that resembled a turtle shell, was popular among divers who valued its tough construction.

The Turtle gets its name from the cushion shape of its case, which evokes the shell of the sea creature after which it is named. 


Seiko Turtle 6309

No actual turtles were harmed in the making of this Seiko Diver. (Source: Hub City Vintage)


It is probably the most popular watch on this list. When you turn it over, it resembles a turtle sleeping on its back even more. This vintage Seiko diving watch was first released in 1977, and in 2016, Seiko reintroduced the Turtle.

With the launch of the Prospex SRP77x collection in 2016, Seiko brought the Turtle into the modern watch market. 


seiko srp777

The OEM SRP777 looks slick as it is, but it has become a popular canvas for Seiko modders. (Source: Chronos Pride)


The Seiko Turtle diver, in both its modern (SRP77X) and historic (6309) forms, is by far the most popular of the Seiko nicknamed watches. It is regarded as one of the best automatic divers for under $500 by many in both the watch collecting, and diving communities.

The Turtle is a nice upgrade from the SKX, housing a high-quality 4R36 Seiko movement and available in a variety of colors and limited editions.

In addition to being a successful model, the Turtle also has a range of aftermarket options, and uses many of the same parts that the SKX uses. We offer a Turtle case, as well as a Turtle Sapphire crystal and custom bezel inserts for the modern Turtle.


Seiko Willard - For the Rock n' Rollers

The nickname was born when Martin Sheen, who played Capt. Benjamin Willard in the 1979 blockbuster Apocalypse Now, notably wore the watch in many scenes from the movie.


seiko 6105 original captain willard

The Ref. Seiko 6105-8110/9 or later known as Seiko Willard is a diver's watch introduced by Seiko in 1970. The watch is water-resistant to 150 meters. (Source: Fratello Watches)


The unusual casing design is instantly recognizable. It's wide, flat, and has a unique crown guard.

The fantastic "traffic light" seconds-hand with its polygonal lume scheme and vivid red dot sweeping around the dial is very unique and makes quite an impression. 

The 6105-8110's combination of screen time, unusual style, and solid feature set made it a great candidate for a modern refresh at a lower price point than the SLA033.


apocalypse now movie scene seiko captain willard

A scene from the movie Apocalypse Now showing the Captain Willard, on Captain Willard. (Source: Mr Stateless)


Fans of the original 6105-8110 will love the new Seiko SPB153 aka “Captain Willard”, especially if they intend to dive to depths up to 200m.

With the 2020 reissues, Seiko brought a classic back to life, and offered the Seiko community a fully modern version of a classic. Like many of the higher-end reissues, there aren't loads of aftermarket parts for the modern Willard, and few people are modding them.


Seiko 62MAS - The First Diver

In 1965, Seiko produced the 62MAS, which was the Japanese company's first professional diving watch. The moniker "62MAS" is derived from the reference number's first two digits – 62 – and MAS, which stands for "auto[MA]tic [S]elfdater," or an automatic movement with date.

The Seiko "62MAS" is the company's first professional dive watch, featuring the much-desired tiny crown from the beginning of its production run in 1965. Seiko employed a smaller crown of 5.5mm as the big novelty.


seiko 62mas

Despite being the first of its kind, Seiko instantly nailed the design of the 62MAS diver. (Source: Fratello Watches)


Another intriguing feature of watches from the initial series is that the distinctive dolphin etching on the caseback was etched lighter to begin with, and many of them have worn away, leaving only the case number visible on the back.

The 62MAS has a quick-set date functionality, which was groundbreaking at the time because few other brands had the capability.

Many of the 62MAS' design components have been replicated in various Seiko diving watches throughout the years. The dials on these watches are a unique grey-green tint that changes depending on the lighting.


seiko 62mas reissue spb149

When Seiko decided to reissue the 62MAS, it was unsurprisingly an instant classic. (Source: Monochrome Watches


While the modern 62MAS reissues are great watches, the price point makes them a poor choice for modding. On the other hand, we offer a 62MAS style case that will accommodate Seiko SKX parts, with the exception of the SKX bracelet.

If you want to make your own 62MAS – let us help you with an amazing Seiko mod! You can learn more about the 62MAS in this previous blog post.


Many Ways to Make Your Own Seiko Mod


Seiko has created some of the most interesting and functional watches over the past 50 years, and if you want to create your own Seiko mods, here at NamokiMODS, we offer Seiko mod parts that are going to deliver the quality you deserve.

If you want to create your own Seiko diver, or need Seiko Samurai parts or Seiko Turtle parts, we deliver a wide range of Seiko mod parts to choose from.

We also have an outstanding line of Seiko SKX aftermarket parts to offer, so you can make the Seiko mod of your dreams. Have a look at our catalogue, and keep the Seiko community interesting with great new Seiko mods! 

June 08, 2021 — Jeremiah A


Kevin said:

The Turtle start available on the November 2015 and is not in 2016. I remembered it as I was looking for a new watch for the coming Christmas present to myself.

NAM said:

Excellent article. I have been a Seiko fan for many years.

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