Monochrome Watches
An online magazine dedicated to fine watches

Seiko Professional Specifications – PROSPEX

| By Evan Yeung | 6 min read |

Dive watches have come and go throughout history; the most recognizable of them are pieces from Rolex and Omega. Submariners and Seamasters have graced the wrist of many, with some even saying it’s the perfect tool watch to wear. But the folks from the JDM (Japanese Domestic Market) would beg to differ…

Much has been said about Seiko watches in the past, but for the likes of Seiko’s PROSPEX line, it has been fairly limited.  Readers of our website may have seen one of them here and another one here. But what really makes the PROSPEX a piece worth having? Allow me to offer a different perspective, the PROSPEX perspective…

seiko SBDX011

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The PROSPEX, as the name implies, simply means “Professional Specifications”. It is Seiko’s answer to the professional world that desires nothing but the very best from their watches. As such, professionals and fans of the lineup alike have deemed it as the quintessential high-end Seiko tool watch to own.

A little history lesson will tell you that the popularity of a certain activity called SCUBA (Self-contained underwater breathing apparatus) diving was on the rise back in the 1960s. We all know that the ability to time the dive was crucial to every diver, and the outcome of which on the horological industry was game changing. Dive watches have become the most popular timepiece in town. Every watchmaker around the world race to produce such a piece, and in it the original Seiko diver watch was born – the 6217. The year was 1965, it was Seiko’s first ever dive into the world of ‘high-end’ Professional Divers and also one of the reason that made Seiko divers an icon that it is today.

Seiko 62MAS

From then on, Seiko has been manufacturing all sorts of watches dedicated to the sport. Ranging from affordable quartz pieces all the way to robust high-end automatics. With the latter becoming what was known as the PROSPEX.

PROSPEX watches are not to be confused with Seiko’s standard mechanical line-up of watches. The build quality of these watches are far from cheap and they’re very much akin to that of a Rolex piece. A high-end precision instrument that came from the brand that was famous for cheap-end quartz. Speaking about build quality is just the tip of the iceberg here. The PROSPEX brand is rich in cutting edge technology.

Seiko prospex collection

Seiko’s PROSPEX is also one of the leading innovators in terms of dive watch advancement. Allow me to enumerate a few of them: The PROSPEX is the first diver piece to adopt a titanium case in lieu of the standard steel case, the first to put a quartz movement in a professional dive watch, the first to use ceramic shroud for deep-sea diving, the first to use a hybrid analog digital watch with an alarm and the list continues. To top it all off, the pieces are powered by Seiko’s very own in-house movements, and we all know they are one of the best in the industry today in every respect.

Although the PROSPEX line is not limited to dive watches, the lineup offers a wide variety of precision pieces dedicated to each profession that requires them. Consisting of automatic or quartz movement, analog or digital display, the PROSPEX line is not easy to get around with. It being a Japanese exclusive makes matters even worse. Most folks can’t even tell the difference between a standard Seiko from a PROSPEX piece.

Seiko prospex collection

But suffice to say, not all PROSPEX pieces gained favorable response among enthusiasts, each new introduction was a hit or miss for Seiko. Some became successful while others don’t. But when they do, they hit it big time, and most of the time, you probably already guessed it, it’s a diver’s piece. The accumulated knowledge on dive watch advancement they’ve earned is not to be trifled with. It’s no wonder that the PROSPEX pieces are sometimes stereotype to being solely Seiko’s divers line. Despite this, the PROSPEX still adhered to their dedication to the brand, and that is to create the very best from Seiko’s technology, for professionals and aspiring professionals alike.

To give you a glimpse on what PROSPEX is all about, let us look to its most iconic piece of them all – the Marine Master Professional or as it is more known as the “Tuna”. Seiko collectors have this fondness for naming Seiko pieces since the inception of their dive watches. The “Tuna” along with the other PROSPEX piece were subject to naming by collectors of the brand, with some even debating on what name to coin the watch with every time a new design comes up.

seiko SBDX011

This happens not only for Seiko pieces but also for most of the Japanese made watches out there. So why “Tuna” for the Marine Masters? The coining of the term “Tuna” on the Marine Master was because of its resemblance to a can of tuna. Others call it the “Hockey Puck Watch” but “Tuna” for its simplicity gained the acceptance among collectors. The Seiko Tunas came with all sorts of variation, with differentiation mostly on its depth rating and movement used. To live up to its name, we look no further than to the grand daddy of them all – the SBDX011, taking home the title of “Emperor Tuna” nickname for its huge wrist presence and 1,000m depth rating.

Seiko 8L35The “Emperor Tuna” houses a movement that is coveted by many. It uses a Seiko in-house caliber 8L35, which is a variant or simply put, an undecorated movement similar to that of the 9S55 (movement used in the Grand Seiko line, another JDM collectible).  The 8L35 is a movement worthy of the PROSPEX name, running at 28,800 vph, a power reserve of 50 hours, a date indicator, hacking mechanism and automatic winding with a precision of +/- 15 sec a day (can be calibrated and adjusted). It is simply a no nonsense movement that is built to last in extreme environments. No frills, no gimmicks, no see through case back… Just a simple durable movement that is made for the oceans.

All in all, the Seiko PROSPEX particularly the Emperor Tuna is in short the best that Seiko has to offer. Everything from build quality, to the movement, to the history are nothing short of what a true professional yearns for. It’s a badass piece that can go toe-to-toe with the very best the industry can offer. With new pieces coming out every year coupled with innovative technology on the horizon, plus the occult-like vintage scene in the market today. The PROSPEX Marine Master, may probably change your mindset on what Seiko watches truly are. Now I wonder how much the foreign exchange rate is for the Japanese Yen these days…

Other notable PROSPEX pieces are the Landmasters, the Fieldmasters and of course the ones that are powered by Seiko’s patented Spring-drive system.

Photo credits for photos 1 and 5 goes to Adam from Purists for allowing us to use his photos. Many thanks to Shannon for letting us use photo number 3 and 4.

5 responses

  1. Just got SBDX011 today! Very happy. … What do you think about the latest model SBDB008 spring drive 600m golden tuna limited edition of 300 pieces? Does this one knock our Emperor Tuna automatic 1000m down?

  2. SEIKO is one of the few companies which deserve to always have its name written in capitals. We all love the exotics, but if every other watchmaker somehow went bankrupt, we’d all be able to find a timepiece for our taste and budget. How many other brands can you say that about?

  3. Thank you for using my photos. I still have the SBDX001 & SBDB001.


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