Citizen NY0040 Promaster vs Seiko SKX779K BlackMonster

Hi everyone,

Are you ready for a legendary battle between two icons in the entry level diver market ? 

Then lets not waste any time.
In the left corner the Seiko SKX779K nicknamed “BlackMonster”

In the right corner the Citizen NY0040 Promaster nicknamed “the underdogg” by yours truly.

After having owned the Seiko for years and since recently I own the Citizen Promaster, I feel it’s time to compare these two icons.
These watches are very similar but differ on various points, the one you will eventually pick will have much to do with personal preference. You can’t go wrong with either of these watches to be honest.

Let’s start with the Seiko
I have owned this watch for more than 8 years and recently sold it. These watches are a classic case of hate it or love it. The reason I was able to sell the watch without losing any money is the fact these watches have true cult status. The Seiko first came to the market in 2000, and a few years later with the internet developing, people started writing about these watches and making video reviews. This watch is the definition of a tool watch and has a big fan base. With tool watch I mean a very robust watch that can take quite some beating. Watches made with a certain task in mind and performing under extremes.

Seiko do not fabricate the Black Monster no more, this adds to their exclusiveness. Since a few years there is a second generation monster on the market, almost all colours are available, in the beginning there was only the black monster and an orange monster. 

People love these watches for it’s design or the lack of it. People also respected its ruggedness. Quality wise it will put much more expensive watches to shame, if you can overcome its bulky appearance you will respect it. Definitely an icon of a watch, every watch enthusiast should have owned one for at least a few months.
The lume on this watch is legendary, light it up and it will shine bright through the night. Also Seiko uses a hardlex crystal, it is not necessarily very scratch resistant but it can handle the force of impact of objects better than sapphire glass. Last but not least this watch is an ISO certified diver making it a perfect scuba diver.

Moving on to the Citizen Promaster

The watch I replaced my Seiko with is this Citizen watch. Such an underdog compared to the Seiko but it has the same built quality and is in my eyes a little more refined. I loved the tool like appearance of the black monster but over the years my taste changed somewhat. I really like and respect automatic dive watches, so I replaced the Seiko with this Citizen NY0040 Promaster watch. Available for about 200 euros which is about the same as for the Seiko on the rubber strap. 
This watch came to the market in 1997, it wears a lot smaller then the Seiko. If you have smaller wrists like me, than this will fit you better. On a metal oyster bracelet it can even become somewhat of a dress watch. Definitely less bulky looking then the monster.

Guess the Seiko wasn’t nicknamed monster without a reason. For some people this watch is quite small when you compare it to normal standards, but soon you get used to it and sometimes wonder why we all have the need to wear bigger watches. 
Another cool feature is the fact that the crown of the watch is at the 8 o’clock position which is quite unique. The Seiko has the crown at 4 o’clock and that was nice, still occasionally the crown was digging into your wrist / hand. With the crown at the 8 o’clock position this does not happen anymore. Only downside is that winding and adjusting the watch is less easy since the crown is located at the left side of the watch. But hey, you adjust the watch, wind it and wear it. 

Let’s compare these watches step by step.

Let’s start with the Movement
The Seiko watch has the 7S26 movement with day date functionality. This automatic movement has a maximum power reserve of 40 hours. It has 21 jewels in its movement and ticks with 21.600 vibrations an hour. This comes down at 6 ticks a second. 

The movement was first introduced in 1965 but re-released in 1996 and in the basis it has a traditional spring and has a non-winding mechanism. Furthermore it is a non-hacking movement. These jewels make sure there is less friction in the movement. Watches typically have between 17 to 21 jewels, the more jewels does not make the movement better or more accurate. Quartz movement have way less jewels since they are battery powered. 

Optimal temperature for operation is between -10 and +60 degrees. The diashock system makes it resistant to heavy severe shocks. All watches with movements from the 7S family are quite robust to external forces. Quality wise and price wise these movements are definitely one of the best value for money.

Now the Citizen, also a automatic watch, has the Miyota 8203 movement, also 21 jewels with 21.600 vibrations per hour. Claimed power reserve of 45 hours, some sources mention 42 hours which is more then the Seiko. This is also a non-hacking movement but it does have the option of handwinding. Accuracy for this movement is between – 20 up to 40 seconds a day. But other sources say – 10 up to 20 seconds. From my own experience even though I only own this watch for 6 weeks, I must say accuracy is much better then the Seiko. Maybe it’s because I am lucky or wear the watch more often then I did the Seiko. Out of the box the Miyota movement seems to be more accurate, that is my experience.

So how about accuracy ?

The Seiko runs either slow or fast, up to 20 seconds slow a day up to 40 second fast a day. There are ways to “train” your automatic to become more accurate. Some people let their watch sleep upside down, this apparently has something to do with the wear and tear of the movement, and in that way you can adjust accuracy. Myself I did not experiment with this, but its what some sources claim.

Some people buy automatic watch winders to keep the power reserve of the watch full even if they don’t wear the watch. The watchforums tells me that some people have been able to get the 7S26 movement down to +/- 5 seconds a day.

The Miyota 8203 also has a long track record of being an accurate workhorse. It difficult to compare the two movements, the only difference is the fact that the Miyota movement is windable and tens to be calibrated more accurate than the comparable 7s. The rotor only winds in only one direction, the 7s is bidirectional.

Also when adjusting the day and date I can’t help getting a feeling this is kind of a cheap movement. Again this is just a feeling, the Miyota is quite solid instead. The Miyota is used in many watches and brands with various price points, while the 7s movement is largely used by Seiko itself.

Both movements are around for more then two decades with a good track record, both being solid, affordable, and the perfect workhorse for dive watches.



Case Width: 42mm

Lug-to-Lug: 48mm

Lug width: 20mm

Thickness: 12mm

Crown Diameter: 5.5 mm


Lug-to-lug: 48mm

Thickness: 14mm

Lug width: 20mm

Case Width : 42mm (without crown), 47mm (with crown)

Cool factor

Many people will say the black monster is cooler since it has a more distinct look about it. That the exact reason I bought the watch in 2011. Back then it came with a rubber strap making it a very comfortable watch, years later I bought the metal bracelet, this made the watch stand out even more, but in all honesty, it made the watch too bulky and with a metal bracelet more prone for scratches.

Now 8 years later I sold it because the bulkiness of the watch made it harder to wear on a daily basis. So I only wore it in the weekends, in the end I barely wore it at all and decided to sell the Monster to another enthousiast. Luckily for me the watch did not depreciate in value at all, so tell your bookkeeper this is a solid investment.

The Citizen is more civilized in a way. This watch can easily be a daily. And I do, I now wear an automatic all week and its reliable and accurate. Something that should not be taken for granted, especially at this price point. 

In terms of coolness I will let the Seiko win, just because it is an icon and more outspoken than the Citizen. Again personally after many years of owning the black monster I can appreciate the subtleness of the Citizen. 


For me personally I pick the Citizen, more subtle, smaller and drawing less attention to itself and probably more accurate. This watch will get more wrist time, i already know that.

It’s a fact you can’t go wrong with either watch. If you dive on a weekly basis, the Seiko is probably better, the lume is outstanding and the watch is in terms of design very much tool based. This is a daily driver.

Also the Citizen is an ISO based diver, but does have the characteristics to make it a daily watch. 

It all depends on taste, spec wise the watches are almost identical.

Accuracy in a dive watch is important, but the people that understand the inner workings of these movements know that they will always run either slow or fast. 

If you value accuracy very much get a solar powered and radio controlled G-shock instead. The best watch for that job, if you like the tech of automatics, pick one of the two watches I just reviewed.

Any questions for me, don’t hesitate to leave a comment in the comment section under this video. Feel free to share this video on watch forums.

Thanks for watching, see you guys in the next video. 

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.