Seiko makes hundreds of different watch models. They have different prices, designs and functionality. Good news for watch collectors, but confusing for someone who just wants a good watch.
We look at “consumer” Seiko automatic watches for men, costing from less than a hundred to a few hundred dollars. We’ll show you the real difference between the models, and how to choose the right one for you.
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Seiko Automatic Versus Kinetic Watches
Seiko “Kinetic” watches are quartz watches that are powered by a small electrical dynamo inside the watch. They will not be covered in this article.
Why Automatic Mechanical Watches?
“Automatic” or self-winding mechanical watches have a weighted wheel that automatically winds the watch’s main spring when you move your wrist. While less accurate than quartz watches (plus/minus 15 seconds a day compared to plus/minus 15 seconds a month), they do have a few advantages.
The main advantage is that there is no battery to change every few years. Even solar quartz watches (or Seiko’s Kinetic – electronic quartz movement driven by a mini dynamo) need battery changes – their rechargeable battery only lasts 5 to 10 years. While mechanical watches don’t last forever, Seiko automatics are commonly reputed to last up to 20 years without servicing (Seiko recommends servicing at a watch shop, every 3 years).
This “no batteries” advantage is magnified when you start collecting watches. Let’s say you have 5 to 10 watches that you wear for different occasions. With battery-quartz watches, chances are high that sooner or later a watch that you pick will have a dead battery. With an automatic watch, you can be confident of it working immediately, without a trip to the shop to change the battery, even after years of sitting in the drawer.
If you swim or dive, “no batteries” means not having to open up the watch to change the batteries, potentially compromising the water-proofing of the watch.
For entry-level automatic watches, Seiko stands out for a few reasons.
Seiko has a history and reputation for making quality watches since the 1960s. Some watches, such as the 6105 Diver’s watch worn by Martin Sheen’s character in Apocalypse Now, have become collectibles.
For low-cost automatic watches, four brands of calibers (mechanisms) dominate the market. They are from Seiko, Citizen (branded as Miyota), Sea-gull (from China) and ETA (the Swiss watch conglomerate that includes Swatch). Other brands, for example Invicta, often buy watch calibers from one of these four companies and only make the casing of the watch.
Seiko makes all the components of their watches, from the Hardlex glass crystal to the watch mechanism, down to each gear, screw and spring. While this might not sound like much to the average person, it’s a big deal to watch collectors.
The Difference Between Various Seiko Watches
Most low-end Seiko watches use the same caliber (mechanism or watch movement). The difference lies in the casing of the watch and its features. Watches with higher water resistance generally cost more.
This is Seiko’s list of recommended use for different water resistance ratings (1 bar is 10 meters of water pressure):
Seiko considers 3 Bar (30 meters) water resistance to be splashproof only, not even safe for taking a shower. For bathing, you’ll need at least a 10 Bar (100 meters) watch.
There’s a difference between a 20 Bar (200 meters) watch and a “Diver’s Watch 200 Meters.” While the water resistance rating is the same, the Diver’s Watch has a screw-down crown for more reliable protection.
On Seiko watches, the caliber is usually printed on the face of the watch, between 6 o’clock and 7 o’clock. The print is very small – you’ll need a magnifying glass to read it. The caliber is also engraved on the back of the watch, in a larger font.
The 7Sxx and 4Rxx Seiko Calibers
The Seiko 7S26 and 7S36 (minor upgrade to the 7S26) calibers were Seiko’s workhouse calibers for decades, powering their entry-level and mid-level automatic watches. Official accuracy numbers from Seiko are hard to find but different websites claim ratings of plus/minus 45 to plus/minus 15 seconds a day. Compare this to the high-end 9Sxx caliber used in Grand Seikos – costing thousands of dollars – which Seiko rates at -3 to +5 seconds a day.
In actual use, owners report anything from plus/minus 5 to 15 seconds a day for 7Sxx. Seikos are factory-set to run a bit fast. After a break-in period of a few months, the watch will settle down and run more slowly. If you want to send your watch to the shop for adjustment, wait a few months first. When adjusted, the watch should be able to maintain plus/minus 15 seconds accuracy a day, or better.
While known for their reliability, the 7Sxx calibers lack “hacking” and “winding” functions. Hacking means that when you pull out the crown to adjust the time, the seconds-hand stops. This allows you to set the watch more accurately, down to the second.
“Winding” means that you can wind up the main spring of the watch by turning the crown. While this might seem like a basic feature, it’s not necessary on automatic watches and is left out on simpler calibers like the 7Sxx. The disadvantage is that to wind up a run-down watch, you need to shake it.
In 2011, the 4Rxx caliber was introduced. It is similar to the 7Sxx caliber, with the addition of – you guessed it – hacking and winding. Remaining the same were two entry-level features of the 7Sxx caliber – a modest 40 to 41 hour power reserve (a fully-wound watch can work for 40 to 41 hours without being wound) and a 21600 beats/hour frequency (6 beats/sec or 6 ticks/sec).
High-end calibers such as the 9Sxx used in Grand Seikos, have a slightly higher 28800 beats/hour frequency (8 beats/sec), which helps it keep more accurate time. The 9Sxx has a 72-hour power reserve.
There is more information on the 4R36 caliber at the Watcharama website:
Seiko has been switching its automatic watches over to the newer 4Rxx caliber but many 7Sxx calibers continue to be sold. Unless there is a specific watch design that is only available in 7Sxx, you should hold out for a 4Rxx caliber watch.
Seiko 5 Watches
The Seiko 5 series are Seiko’s cheapest line of automatic watches, with some models being available for less than $100. Using 7Sxx or 4Rxx caliber watch movements, they are reliable and reasonably accurate.
Their low cost means that Seiko is free to experiment with a wide variety of different designs. Similar to the Swatch philosophy, many new models are released every year. If you like to collect watches for fun, not for prestige or investment, a Seiko 5 makes a lot of sense.
Plain “Seiko 5&Prime watches are “dress” watches that go well with formal attire. “Seiko 5 Sports” watches are for casual use and have a waterproof rating of 100 to 200 meters, compared to 50 meters or less for plain Seiko 5s.
The Seiko 5 version of the popular Seiko 200m Diver’s watches are the SNZF series. They are rated to only 100m and don’t have a screw-down crown so aren’t real Diver’s watches, but have similar rotating bezels:
- SNZF17 – Seiko 5 version of the SKX007
- SNZF15 – Seiko 5 version of the SKX009
Seiko has some information on the history of the Seiko 5:
Seiko Superior Watches
Seiko Superiors are a step above Seiko 5s, with water resistance rating of 100 to 200 meters (but lacking the screw-down crown of dive watches). Confusingly, some Seikos are Seiko 5 Superiors but these are rare and should be considered plain Seiko 5s.
Some watches are called Superior Diver’s Watch. From the price and the screw-down crown, these should be considered Diver’s 200m watches.
Some Superiors have a 24-hour sub-dial. The time on the sub-dial cannot be set independently from the main hour-hand. It serves more as an am/pm indicator than a dual-time indicator.
Seiko 200 Meter Diver’s Watches
These are the most sought-after Seiko automatics (make sure that it says “200m Diver’s” on the watch, not just “200m”). Using the same caliber as the Seiko 5s, they are much tougher – with a screw-down crown, heavy stainless-steel body and thick glass crystal. Even if you don’t scuba-dive, the screw-down crown means that the crown won’t be accidentally pulled open if it snags on anything.
They are the perfect “beater” watches for rough work – gardening, washing the car, fishing, sports. They are tough enough to survive almost any abuse, and cheap enough that if it gets lost or scratched-up, you won’t mind.
The most popular are the SKX series. Individual models even have their own nicknames.
- SKX007 Black bezel
- SKX009 Blue and red bezel – “Pepsi”
- SKX173 USA market version of SKX007
- SKX779 “Black Monster”
- SKX781 “Orange Monster”
The SKX series uses the older 7Sxx caliber. The new SRP series, launched in 2012, is an updated version of the SKX series. With the new 4Rxx caliber and slightly different design, these are the Seiko Diver’s watches to get:
- SRP307 – 4Rxx version of the SKX779
- SRP309 – 4Rxx version of the SKX781
More about the SKX and SRP series:
Seiko Prospex watches are higher-end models, costing from a few hundred to a few thousand dollars. Not all Prospex watches are automatics, some are quartz.
The automatic Prospex models have more advanced calibers, such as the 6Rxx or 8Lxx – 50 hours power reserve, 28800 beats/sec (8 beats/sec) for higher accuracy. Some also have higher water depth ratings – 300m to 1000m. Popular models include:
- SBDC001 “Sumo”
- SBDC007 “Shogun”