How to tell when your Seiko watch was made (Part 1)

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So, you’ve just purchased a used or new Seiko watch. Congratulations! Have you ever wondered when your watch rolled off the assembly line at the factory? In other words, when was it manufactured? Questions relating to the production date of Seikos frequently pop up in various watch forums from time to time.

Well, in case you didn’t know this, the answer to this question actually lies in the set of numbers that are etched or printed on every Seiko watch made. Chances are if you ask watch store assistants when that particular Seiko watch you’re interested in buying was made, you’ll get a blank expression from them. Either that, or they’ll come up with an excuse for not knowing by saying that it’s a new arrival (yeah, right!) 🙂

You can’t really blame them for not knowing because watch sellers are in the business of selling watches, period. From my experience many Seiko dealers aren’t watch enthusiasts themselves. They’re more interested to get a sale from you rather than discuss the history or significance of that Seiko watch that you’re looking to purchase.

Well, I’m a firm believer that knowledge is power. And if you have that knowledge, you have an edge over the seller that could be very useful. Especially when it comes to bargaining for a better price for that new, old stock (NOS) Seiko that caught your fancy.

File photo of a typical watch store in Kuala Lumpur. Chances are that the store owner in the picture doesn’t even know when the Seiko watches that he sells were made, 🙂

If the store owner senses that you know more about that watch than he or she does, there’s a good chance that you can bargain for a more realistic price. I have gotten a few discontinued Seiko watches in this manner, saying “Hey look, this watch is eight years old! It can’t be worth the price you’re quoting me!”

Fortunately for me, the watch dealers relented to my counter offers and I got them for the price that I wanted.. They probably figured out it’s better to sell off the watch now than risk their capital tied up in old stock that nobody else is interested in.

Let’s find out how to date your Seiko watch and I don’t mean socially! 😉

Where to look for the serial number

To locate the serial number, you’ll need to flip over your watch and examine its caseback. Seikos with solid casebacks (plastic, stainless steel or titanium) will have the 6-digit serial number etched in a straight line. Those that come with glass display backs like modern Seiko 5’s have the numbers printed horizontally on the glass display back but the numbers are usually faint and difficult to read.

Higher end Seikos with display backs, like the 6R15 caliber Premier or 7L22 Sportura for example, have the serial number engraved not on the glass but on of caseback’s rim.

Here are three examples of Seiko casebacks depicting their serial numbers.

Type I: Seiko 5 glass display back:

Seiko 5 glass caseback

Basic Seiko 5 models made from the year 2002 onwards have clear glass display backs as you can see above. The 6-digit serial number is always located at the opposite end of the “SEIKO” text. The numbers are faintly stamped from the inside of the glass. You’ll have to tilt the caseback towards the light to read the numbers properly or better still, use a magnifying glass. The Seiko 5 in this picture is from February 2004.

Update: Some very recent model Seiko 5s have the serial number printed not on the glass but along the caseback rim. If you can’t see the serial number on the glass, then look for them on the caseback rim (usually located on at the bottom part of the caseback).

I guess Seiko decided that it’s easier and cheaper to produce spare display backs without having to etch the serial number individually


Type II: Display backs on higher end models:

Non-Seiko 5 glass caseback

In more expensive Seikos with glass display backs like the Premier 6R20 pictured above, the serial number is usually found engraved along the rim of the caseback. Unlike the rest of the identifying text, the serial number is printed in a straight line. Why doesn’t the serial number follow the curvature of the rim? I’m not sure but I think casebacks are manufactured en masse and the individual serial numbers are stamped on later prior to packing and shipping from the factory. Anyway, the Premier pictured above was made in August 2007.

Type III: Solid metal caseback


The majority of Seiko watches come with solid metal casebacks (stainless steel, solid gold, gold plated or titanium) and the serial numbers are also stamped in a straight line. Pictured above is a the caseback of an SKX007K Seiko dive watch. Reading numbers off solid metal casebacks is pretty straightforward. The Seiko diver above is from November 2003.

How to the serial number works

Every Seiko watch manufactured is given a 6-digit serial number. There are however exceptions to this rule. Seiko watches made prior to the late 1960s, most probably 1967 have 7-digit serial numbers instead. Limited edition models with unique sequenced numbering, e.g. 123/300 (denoting the 123rd piece out of a total of 300 pieces) usually don’t have serial numbers.

Limited edition Seikos are usually made within a very short time frame – perhaps not more than a few months in the year it was introduced. In this case you’ll need to know the intimate history of the model – for example, the SBDX005 Historical Collection 600m diver was released in 2000 with 1,000 pieces made. You may not know the exact month the watch was made but suffice to say, the production year couldn’t be any later or earlier than 2000.

To simplify things, I will use the 6-digit serial number convention. This table below describes the structure of the serial number.

Digit Position Description Characters used Notes
1 Production year 0 to 9 Denotes the year in the decade, not absolute year
2 Production month 1 to 9, “0”, “N” and “D” 1 to 9 denotes months of January to October. “0”, “N” and”D” denotes October, November and December respectively
3 Sequence number, thousands 0 to 9 The last four digits represent the running number of the watch
4 Sequence number, hundreds 0 to 9
5 Sequence number, tens 0 to 9
6 Sequence number, ones 0 to 9

Deciphering the serial number

  • The first digit signifies the year the watch was made. It doesn’t tell you the decade – only the year. This will present a problem because you may not be able to distinguish whether the watch was made in 1997 or 2007. The digits always range from 0 to 9.
  • The second digit denotes the production month. Seiko uses 1-9 for January to September. October is represented by the number 0 (zero, not the letter “O”) while November and December are abbreviated to “N” and “D” respectively.
  • The remaining 4 digits represent the production number of the watch in a sequence. It is generally believed that the first watch produced every month begins with “0000” and the last watch made in that month ends with “9999”. Going by this convention, up to 10,000 watches of a particular model could be manufactured in one month. The sequence number is reset for the following month. Therefore if Seiko made up to 4,900 pieces in February, the last watch produced will have the the sequence number 4900. For the following month of March, the first watch produced will have the sequence number 0000 instead of 4901.

The following table below gives examples on how the serial numbers are interpreted:

Caliber Serial Number Year Month Watch Number
7S26A 717872 1997 January 7872
7T32 8N1030 1998 November 1030
6105 200421 1972 October 421
6138 731999 1977 March 1999
6309 4D8001 1984 December 8001
8L35 259393 2002 May 9393
7S26B 760023 2007 June 23

Jayhawk’s Production Date Calculator

Fortunately there is an automated method of determining when your Seiko was made. Savvy Seiko watch enthusiasts have been using Jayhawk’s Production Date Calculator to check when their watches were made. It’s linked from the Seiko & Citizen Forum and to my best knowledge, it is currently the only automated tool for dating your Seiko watch on the Internet.

It’s easy to use – just enter your movement number and the serial number and hit the Calculate button. There you have it – your watch’s date returned to you in a matter of seconds! 🙂

However, there are a few caveats that you need to know when using the Production Date Calculator:

  • Firstly, the results that are returned to you are based on the accuracy of the internal database table. There may be unintended mistakes in the range of the years entered into the table.
  • The calculator does not take into account for calibers that are made for more than 10 years.
  • The production date calculator does not cover the entire list of Seiko calibers made.

The problem lies in Seiko’s numbering convention as it used only one digit to represent the year. The first digit only signifies the year number in a certain decade (10 years). While it is true that Seiko movements are discontinued in less than a decade, there are however, some exceptions to the norm.

A well known example is its very popular 7s26 automatic caliber. If you enter a serial number beginning with “7” or “8” for a post-2000 made 7s26, the date calculator will return you the years 1997 or 1998 respectively, which is off by a whopping 10 years! Even if you are certain that your watch was made in 2006, the date calculator will still think that it was made in 1996.

Here’s why:

The Production Date Calculator unfortunately doesn’t have the ability to account for calibers that have been made for a decade or longer. It merely checks the first digit in the serial number (the year of production) and compares it with its internal table of calibers with the starting year. Since Seiko uses only one digit to denote the production year, the calculator cannot determine the exact decade the watch was manufactured.

For instance, 7s26a caliber was first introduced in 1996 and therefore it naturally assumes that it was from the 1990s. The replacement 7s26b caliber however, came out in late 2006 but the production calculator does not take this into consideration.

Seiko 5 Superior

Caseback dating dilemma: Was this Seiko 5 Superior from January 1997 or January 2007? It’s actually from 1997.

Manually dating a Seiko watch

Fortunately, there is an alternative to the Production Date Calculator if it returns you erroneous or dubious results. In order to do this, you will have to date the watch by manual means that can give you an approximation or the exact the decade the watch was made.

If you’re interested in pursuing this topic, learn how to manually date a Seiko watch here.

Did you enjoy this post? Why not leave a comment below and continue the conversation, or subscribe to my feed and get articles like this delivered automatically to your feed reader.


Dear Quartzimodo.
First, many 10x for your great help.
Second, I’ve bought the SRN001P1 today.
How can i know where is it made?
The number is 843123.
The caliber is 5M54-0aa0.

10x a lot!

Hi Roy,

Congratulations on your new Seiko SRN001P Kinetic watch. It’s made in Singapore on April 2008. The 5M54 is a relatively new Seiko caliber.


Hi Quartzimodo,
Yesterday I bought an old Bell-Matic at a thrift store. I am trying to date it. The Model # on back is 4006-7019 and on the face is 4006-70207 AD. The serial number on the back is 7000031. Thanks for your help.

Hi Clemualb,

The serial number that you gave me is 7 digits long, instead of six. Can you confirm whether your Bell-Matic has “waterproof” or. “water resistant” markings on the caseback?


Dear Quartzimodo,
Just bought a used 9020-7010, SNo. 560117. As I learned from your detection rules, the watch was made in June, 1995 (or 1985?). The current product no. is 177, right? Is there a source that can tell how many pieces of that watch were produced? (It has 14 kt gold back. No steel!)
Regards, Detlev from Munich

Hi Detlev,

I’m not familiar with the Seiko 9020 quartz movement but designs based on this caliber suggest that it’s an 80s watch rather than the 1990s.

Therefore it’s quite probable that yours was from June 1985. Although your serial number has the number 177, it is actually piece #178, because the first watch made in any month has the ending 4 digit numbers starting with “0000” and not “0001”.

Unfortunately I have no idea how many pieces of your particular model were made. You’ll have to contact Seiko Japan to get the information.

hope this helps,

It says Water Proof. A member of the Bell Matic blog dated it at Oct 1967. Here is my post there with pictures of the watch.,

Hi Clemualb,

The reason that I asked for the serial number verification is because a 7-digit serial number applies to vintage Seiko watches made between 1966 and 1967. Most Bell-Matics I’ve seen in pictures (I own two myself) are from the early 1970s. It’s quite rare to see one that’s made in the late 60s. So there you have it – October 1967. You have one of the earliest Bell-Matic models, which is a rare occurrence. The “Water Proof” marking also confirms that your watch has to be from 1967 and not 1977, because it if were from 1977 (about the time the Bell-Matics were discontinued) it would have “Water Resistant” marked instead.

John Nelson (John N) is a contact of mine and he used to run a site dedicated towards Seiko Bell-Matics; he would know about the subject more intimately. I bought a 4006-6040 from him two years ago as he was liquidating his collection.


Hi, I have a Seiko lady’s watch that is very confusing to me. The serial # is 880186. It also has the # 55105 on the face and inside it is 17J and 11A witch i am unable to find any information on it. I would appreciate any information you can give me. Thanks, Tammy

Hi Tammy,

Not much is known about the hand winding Cal 11A as to when it first appeared and when it was discontinued. However, it’s believed that this caliber was introduced in 1970.

My best guess is that your watch was made on August 1978, based on your serial numbers on the back of the watch. The numbers on the dial refer to the dial code and is not used for dating the watch.

Hope this helps,

Hi Quarzimodo

I recently received a SNK315K from the US, 1D1107, and I notice that the caliber is 7S26c, whereas my SNKE53K1dated June 2011 is a 7S26b. Does this mean Seiko has upgraded the 7S26 caliber recently?

Incidentally, do you think Seiko solar is superior to Citizen Eco-drive?

Hi Foxbat,

I haven’t been poking my nose in watch stores for a long time, but word has it from the Seiko collector communities is that the 7s26C version did appear sometime in 2011. Some believe that the 7s26C has a more pronounced, elevated pinion in the movement for better height clearance for the main time hands. If this is true, then it should solve cases of sticking second hand that tend to rest exactly where the minute hand lies when the main spring is nearly unwound. So far I noticed that one of my watches (7s26B caliber) has this problem.

Thanks for reporting your watch production dates. Since you have observed your SNK315K is from December 2011 and your SNKE53K from June 2011, this narrows down 7s26C’s debut between the months between June and December 2011. More feedback from owners having the newer 7s26C movement are needed to pinpoint the exact month Seiko introduced the 7s26C.

The new Seiko solar powered watches should be at least equal to Citizen’s Eco Drives. Actually Seiko has had solar powered watches dating to the late 90s or early 2000s, but they weren’t as popular as Citizen Eco Drive watches. For Seiko, they were busy pushing their Kinetic technology while Citizen had no choice but move forward with what they’re already good at – light powered watches. Once upon a time, Citizen made a few models based on its Eco Drive Duo technology (solar and kinetic movement charged), but they were quite expensive. Those watches were probably more efficient at charging using sources of light than the wrist movement, therefore it made the “kinetic” charging method redundant.

I might buy one of those nice Seiko Solar chronographs this year. I saw quite a few models when I visited Singapore last October and was tempted to buy one, but I’ll wait for newer solar powered chronographs to appear.


Thanks again Quartzimodo

The reason I asked about Seiko solar was I saw a SNE031 advertised recently and considered buying it. I was waiting for the SNK315 to arrive and discovered that the two watches are virtually identical (37mm across and 10-11mm thick with very similar plain white/cream faces). In the end they were too similar, despite the different mechanisms, so I’ve changed tack (see your chronograph blog).

Incidentally, as I once said before, I have a “venerable” 5M62-0AK0, s/n 386455, which I bought in Canberra on 9 February 2005 (18 months old at the time). None of the documentation tells me what the model (S**etc) is. Is there some way I can find out?

Hi Foxbat,

I Googled for your Kinetic watch and found the reference number. It’s either the SKA196P (white dial) or the SKA198P (black dial).

The SNE-series solar watches are one of Seiko’s latest revivals into the solar powered watch scene and this time they’re putting more effort into promoting them. I expect them to be vastly improved versions of their earlier efforts. Its solar panels are located behind the translucent dial like the surface of a white ping pong ball. Your Promaster AV0031-59A’s solar panels on the other hand, are located at the subdial apertures. It’s best that you view the SNE031 yourself before buying it, in case you prefer solid, opaque dials.


Thanks again. You are a champion!

My SKA is the black 198P. There is considerable similarity to my recently bought SMY115 – which you gave the suffix P, which I assume means that both watches were assembled in Singapore. Does the suffix K indicate Hong Kong assembly?

I shan’t be buying the SNE031. I was looking at it amongst a group of watches but in the end I plumped for a Citizen CA0021-53A, which had features that encapsulated the whole group.


Your education, and that of one or two others, has shown me the absolute need to shop around for watches, especially via mail order.

Hi Foxbat,

Yes, the “K” suffix designates a Seiko watch that is cased in Hong Kong (China). Do note that some models that are exclusive to the U.S. market do not have any letter suffix at all. Some examples include the SKXA35 and SNM035 automatic diver’s models. They are not referred to as the “SKXA35K” or “SNM035K”. U.S. market models also have the country of manufacture printed on the dial to comply with the American Federal Trade Commission labeling laws. For watches that are made in China, they are clearly marked “Mov’t Singapore” or “Mov’t Malaysia” and “Cased in China” in fine print on the dial.

The Citizen CA0021-53A is a great looking watch, but personally I avoid watches with no contrast between the dial and the hands/markers. They’re hard to read the time in dim lighting. BTW, have you ever considered Orient automatic watches before? I have an Orient CEY04002B and it’s a very fine dress/sports automatic, with a power reserve indicator and perpetual world time. For its asking price, Seiko offers nothing like it. A unique feature of the Orient CEY04002B is its sapphire glass display back, which is quite unusual as most watches with see-thru casebacks use the cheaper mineral glass.

This watch is equally eye-catching as the Citizen Promaster E210 series and I’ve often received compliments whenever I wear it. 🙂


Hi again

Three things:

I looked at the SNK315K I received allegedly from the US this week but the curiosity is it does have the suffix K and no origin printing on the face, even with a maginfying glass. Perhaps a US entrepreneur imports for export but not for the US market?

In that regard, I used the hotlink re the Orient CEY04002B and came up with an LA supplier who clearly indicated “USA only”. I subsequently looked at a Singapore supplier just out of interest as my budget and brain are exhausted for the time being. I will probably end up with a simpler Orient power save indicator automatic some time in the future.

I take your point about the CA’s white on white but we all wear watches by circumstances and mood. I go to meetings regularly and generally wear black faced watches like my Citizen BM8430 or my SKA (thanks again for identifying it) or SMY Seiko kinetics which allow me to glance at the time. I have drawn up for fun and some self-indulgent justification a list of my 18 “active” watches and how I intend to use each of them.

But now this 66yo “semi-WIS” is going to withdraw from the field for a while.

All the best, thanks a million and cheers.

Hi Foxbat,

In the early 2000s, Asian market Seikos were available exclusively from Southeast Asian and Hong Kong based sellers. Things have changed since then, with a few enterprising Far East based watch sellers setting up offices in the U.S. to cater for the North American market. Such watches, including your SNK315K Seiko 5 are considered parallel imports from Seiko USA’s point of view.

The Orient CEY04002B is a watch that’s worth saving for, because it’s a lot of watch for the asking price. There is also a Japan market, limited edition model that uses the identical movement but sells for USD2,000. I’ve seen the watch in person and have taken photos of it at my regular watch store. After a year sitting on the shelf, the watch was returned to the distributor as nobody wanted to spend that much on a “mere Orient” watch.

If I could offer some advice, it’s better to save up towards something that’s more unique rather than going for quantity for your collection! Take it from someone who’s owned a little over 80 timepieces. 🙂


Oh dear, Oscar Wilde is winning!

After your last advice I internetted Orient automatics and you are of course right, they are a great idea. The reviews from far and wide are universally, or almost, glowing.

I have ordered a FEU07008DX as a starter, just over $100 delivered and very interesting looking. As to the CEY04002B, what about the slightly more expensive CFA05001B? I prefer the look of the latter and the specs seem very similar.

My only problem with having a surfeit of automatics is keeping them all going. I know you say it’s not really necessary but an Orient site suggests they should be wound at least once a week to keep the lubrication constant.

It’s also suggested that it is best practice to keep an automatic on your wrist for eight to 12hours a day. Obviously with a reasonable number of watches, including potentially five automatics, that won’t happen.

As usual, I look forward to your invaluable advice.

Hi Quatzimodo

I got the FEU and to my surprise and mild disappointment it turned out to be a FEU07005BX instead of the 8D; the former is thicker, heavier and mineral rather than sapphire.

One pleasant surprise is it features a Breitling Navitimer, or copy. The manual doesn’t explain it but googling naut and stat did.

I took you advice, sort of, but went for the CEY04003W0, as you might have foreseen. Unlike you I do like the white on white look; my Citizen CA0021-53A is a particular treasure.

Thank you for all your expertise, advice and interest. After $2000 or so I’ve done my dash and reached a respectable 20 watches so it really is time to stop!

Hi Michael,

Congratulations on buying both (wow!) Orient watches. 🙂 The model FEU07005BX is most probably a recent model as I haven’t been following developments of watches for some time. The scale that’s printed on the edge of the dial is an E6B Flight analog computer which works on the slide rule principle. On watches today, the E6B scale is mostly for aesthetic/decorative purposes as even single engined Cessna/Piper pilots use digital flight computers for navigation. I have several watches with the E6B scale on them and never bothered to learn how to use it, lol..

Your purchase of the white dialed CEY04003W0 didn’t come as a surprise to me (I was nevertheless elated that you chose this model) as from your past comments, you like white-on-white watches. I have only three or four white dialed Seiko models, but their index markers are black, providing some contrast. It’s a good thing that you selected the CEY0400 series, because the small perpetual second hand departs from the traditional long sweep second hand on your other timepieces. Due to its short hand, the individual ticking motion is not discernible to the eye and this gives it a fluid-like motion like the second hand of a Seiko “Quiet Sweep” wall clock or a Seiko Spring Drive watch.

My advice is not to buy too many watches within a short span of time, unless they are on the endangered species list (read: vintage/discontinued). Spacing out your watch purchases will give you time (pun not intended) to enjoy your most recent purchase.

The CFA05001B is a newer model to the CEY0400 series; it sports a different caliber than the latter. Modern mechanical watches don’t really need to be worn all the time – there are millions of unsold automatics sitting in retail stores all over the world that haven’t been “shaken” in six months or longer, but they still work nicely. You don’t need to buy an automatic watch winder unless you own some exotic Swiss mechanical with complications like a perpetual calendar. Such watches can have complex setting procedures, that’s why their owners invest in watch winders to avoid the hassle of setting these watches.

Enjoy your new watches in good health! 🙂


i have, since bought new a seiko quartz divers 150m s/n 531231 and these other numers 7548-700f stainless steele japan. any info on this still great working time piece will be greatly appreciated, value,cost new and year made.i am getting older and cannot remember when i bought it. THANKS in advance for any help, p.s. love your site,richard

Hi Rick,

You have one of the more collectible Seiko quartz diver’s watches. The 7548-700x series are generally well liked by most Seiko dive watch collectors and a Pepsi-bezeled 7548-700F can fetch between USD200 to USD250 depending on the condition and originality. The 7548-700x is commonly believed to have influenced the styling of the SKX007/SKX009 series, automatic divers which appeared in the mid 90s. Your watch was fully made in Japan by Seiko’s Suwa factory on March 1985.

The five jeweled, 7548 movement is robust and long lived. It requires an Energizer 301 or Seiko/Maxell SR43SW 1.55 silver oxide battery, with a 3-year lifespan.

thanks for the compliments! 🙂

Hi Quarzimodo

Thank you for your encouragement and advice.

I agree I have dived in rather precipitately. Fortunately I have decided to stop at 20 with the two Orients. I had expected to stop at 18 but your salesmanship for the Orients was so excellent that I had to expand my collection accordingly. My philosophy is not to have a conventional collection of collectable watches but to be able to have a cross-section of horological ideas and to wear them all at different times, with the possible exception of the Seiko 6139-8002 (still being repaired) and the Citizen 49-9714, both of which have sentimental, rather than practical, value.

I now have five Eco-drives, five automatics, two kinetics (after my purchases over the past three months I agree that too many kinetics would cause problems), three HRMs (as a diabetic I have to keep fit and my weight down) and five assorted quartz watches, of which the star is my 1979 Citizen 49-9714 SF8 calculator; the un-star is my fake G-Shock GA-100, which the G-Shock cognoscenti want me to throw in the rubbish bin but which actually excites my sense of humour.

Incidentally, taking the ideas together of old watches and fakes (or more kindly replicas) I recently googled the serial number of a ten year old Citizen Eco-drive I bought in Singapore in 2002. It turned out to be a BM0730-59A; when I googled that name I found it was discontinued by Citizen some years ago and has become the model for replicas! An ironic turn of events given my recent mania.

I was interested in you description of what I called the Breitling Navitimer derivative. Having googled “stat naut” I found a website that told me how to use it for multiplication and division. I will never use it for navigation as my car and GPS will do that but it will occasionally be useful for rough calculation, mile to kilometre conversion and currency conversion.

So as you advise I have decided to call it a day for a while. I shall enjoy my watches, both old and new, and rejoice in the great advice you have given me.

Just finishing emptying my mother’s house so it can be sold. (She’s in an assisted living facility). I ran across a Seiko with the numbers 7N01 5C39. I’ll probably pass it along to one of my children. I’m not even sure if it’s a man’s or a women’s watch or if it has any value. The serial number is 880742. Can you help?

i purchase a seiko UFO 6138 0011 and i want to know the fabrication date..the number on the back is 448900..thats mean mi clock is from april 1974?

Hi Pablo,

Yes, your 6138-0011 is from April 1974. It’s easy to date 6138 automatics because they only existed in the 1970s. Sadly, as quartz technology became more prominent, Seiko decided to cease production of affordable automatic chronographs in favor of digital watches and quartz chronographs.


[…] of some decade that ends in a 7. 67, 77, 87… something. Decipher your serial number here. How to tell when your Seiko watch was made (Part 1) Reply With […]

i have seiko of my grandfathers.. i dont know weater that seiko is origional or not.. behind watch have writen 750592.. is that serial number origional… and under that 6309-5060 what its means..

Hi ganes,

Without looking at photos of your grandfather’s 6309-5060 I can only assume that it’s an original Seiko watch. From the serial numbers I would say it’s from May 1977.

The watch was fully made in Japan by Seiko’s Suwa factory and its design harks from the late 1970s.


Hi I have a Seiko Sea Lion M55, serial No.6301500. can you possibly date it for me.

Hi Bob,

Sure thing. If you have the Sea Lion M55 Weekdater, it’s most probably a 6119-851x model. It should have “waterproof” markings on the caseback and the 7-digit serial number dates this watch to March 1966.

hope this helps and wear it in good health,

I have a Seiko watch serial No.848466 TL on the back it says water resistant, stainless steel, 6309-8020, number on the strap, Z152. On the black face Day/date, Seiko Automatic 17 jewels, Japan 6309-813LR can you date it please.

Hi Bob,

Your Seiko 6309-8020 is an early model dating from April 1978. The 6309 movement came out sometime in 1976 and those that were manufactured before 1984 were made in Japan. Later 6309 models were Hong Kong assembled until they were discontinued by the late 1980s.

hope this answers your question,

I have a ladies seiko watch that belonged to my mother in law. serial number 038150 stainless steel+base metal gold tone in color. since the first number is 0 would that mean 2000?

Hi Todd,

The movement and caseback number must be known before one can date a Seiko watch. For example, if your mom-in-law’s watch has a movement that was discontinued by before 2000, it would be from 1990, 1980 or even 1970. Seiko made quite a few movements in both quartz and mechanical forms with differing market lifespans, therefore it’s imperative that the movement and caseback numbers are identified first.


I have a men’s Seiko Lassale watch. On the back it says 5L14-600H with A3 in a box. S/N 760088. On the face under the 6 it has “Japan 5L14 6000T”, do you know anything about this watch?

Hi Don,

Seiko Lassale watches are not really my forte and I’ve never really paid much attention to them. The Lassale sub-brand was conceived when the K. Hattori Company (Seiko) bought the Jean Lassale watchmaking company in 1982. At the time Seiko had proudly designed several ultra wafer-thin quartz movements and they fitted them to the initial Seiko Lassale models.

Towards the end of the 1990s when the Lassale lineup was totally discontinued, Seiko had widened the range of Lassale from simple gents’ dress watches with complicated quartz movements such as the 7F68 moonphase and Seiko’s own 7T32 chronograph movements. I’ve never seen a Seiko-branded 5L14 watch before and in my best opinion, the 5L14 was exclusively used in the Lassale sub-brand. Without seeing an actual photo, your watch could be from June 1987 or 1997.

The 5L14 is a simple 3-jeweled, quartz movement with no calendar or second hand (its sister 5L15 caliber has three hands though). It requires a Seiko/Maxell SR920SW 1.55V silver oxide battery which is rated for 5 years between battery changes.

There’s an interesting post on Seiko Lassale watches which might interest you here.


I have a sieko 7t36-6a39 watch, it has chronograph-quartz on the face, it has the moon phase shift option ser number 937542. could you tell me the value on this watch

Hi Danny,

What you have with you is a Seiko model SEJ010J, which was fully made in Japan and was possibly made on March 1989, at the time the moonphase quartz watch fad began. I’m sorry I can’t put a value to your watch, because 7T36 models are considered rare even in the used market. Some 7T36 models which belonged to the collectible, “Age of Discovery” series may fetch at least USD450 in excellent condition, perhaps a bit more.

eBay is a good place to investigate the average winning bids or Buy-it-Now asking prices of 7T36 watches. Not all used 7T36 watches for sale will have uniform values as it will also depend on the exact model. Right now there’s only one live auction for a 7T36-6A40 on eBay, but it’s not completed yet. You might be interested in following the auction to the end to see how high its winning bid will be.



Just picked up a Seiko 5 with Thai numbers today. I believe it’s made in ’99 but would value your input.
serial: 997768
other numbers: 7009-876A
It’s a little beauty.

Hi Nongbrown,

Your special Thai numeral, Seiko 5 would be more likely from September 1989 and not 1999, because the 7009 caliber was discontinued by 1996 and was replaced by the current 7s26 caliber.

It might interest you that the Muang Thong company (Seiko Thailand) in Bangkok has the biggest influence on Seiko watches in Southeast Asia, outside of Japan. It has the decision making clout to issue special editions for the local Thai horology market.

Seiko Thailand has been responsible for coming out with the legendary SKZ201K Seiko 5 40th Anniversary divers back in 2003, the highly collectible Yellow, Red and Blue Monster diver’s models and one-off, Seiko watches commemorating their King Bhumibol’s Anniversaries, such as this one.

Therefore a Seiko watch such as yours was likely to have been originally sourced in Thailand and not sold in other countries.


Hi, Quartzimodo. Long time no speak.

Thanks for the plug. That thread I wrote has had a lot of traffic over the last couple of weeks – partly because it’s also hot-linked in various Jean Lassale related threads on TheRolexForum, Watchuseek, TZ-UK, Orologio&Passioni, etc.

Any queries you get on Seiko 7Axx’s (particularly 7A38’s) and the related Orient, Yema, Cartier Ferrari calibers, please feel free to point them in my direction. ;o)

Regards, Paul.

Hi Paul,

That’s really great! I’ve been off the watch scene for sometime and only stumbled upon the forum site recently. Back in my SCWF forum days, there was very little interest (or none at all) in Seiko Lassale watches and information on them were really scarce. The content material on the Seiko Lassale models was the most comprehensive that I’ve read in a long time, great job on the article. 🙂

The Seiko 7A28 and 7A38 are two quartz chronographs that I’d really like to get my hands on; but very good condition ones are hard to find nowadays.


Hi Quartzimodo

That’s great insight and very helpful. Knowing that, I will be on the lookout for a couple more unique items. This one I found at a Thai Army market.


Hi Quartziguru

I have recently finally got back my treasured Seiko 6139-8002 (or 8010 – my first question) after five months being repaired (the crystal was the issue, I was told).

Two things:

The model number on the rear says 6139-8002, but on the face the number is 6139-8010. Which is it and is this common? I have had the watch since new, which gets me to my second question.

The watch was bought by a friend for me when he was visiting Port Moresby in 1977. But the watch’s serial number is 262996, indicating manufacture in June 1972. Is such a delay unusual or a problem?


I don’t see my automatic divers watch exactly. The back of my case has the wave design but it says Seiko water resist Japan A then the serial number 100800. Then from the s/n on the other side is St. Steel 6309-7049 the second hand has a little round thing at the end of it. I have the day and date window and the days are Spanish/English. Does this ring a bell?

I have a SEIKO Quartz 5y23-8a69 serial # 180903 it is a hand me down was stored a few years the battery was removed I need to know which battery it takes & any other info will be greatly appreciated TY

I have a ladies seiko two tone dress watch. The front face says automatc, 17 jewels. The back says 780005 and 4206-0519, water resistant, s. Steel basse, movement singapore. WAS PURCHASED IN Aruba in The late 1990’s. What type of battery is needed? Thank you.

Hi lisamarie,

Thanks for your question and I apologize for not being able to reply sooner. You have a self-winding, mechanical watch which is also referred to as an “automatic” watch. Automatic watches are purely mechanical and are not electronic. As such, they are powered by a tiny main spring that drives the watch mechanism and do not require any battery whatsoever.

In the case of the 4206 day/date caliber, you can actually wind the watch manually by carefully winding its crown in its pushed-in position. The 4206’s winding mechanism isn’t that efficient therefore Seiko provided an auxiliary hand-winding capability to this movement. Your Seiko watch is a U.S. model and was made on August 1997. By the early 2000s, the 4206 caliber was replaced by the 4207 (with the same features) and is still used in Seiko 5 automatics for ladies.

hope this helps,

we bought seiko watch 5 from someone… it doesnt have box anymore… tha warranty card says… model no. 7009 watch no. 196050.. the no. on the warranty card and the back of the watch do matches… but im still confused if its real SEIKO % watch… please help

Wow! what a great site! Amazing you are, and I thank you!
I need a watch battery and was given this beautiful watch about a year ago but I know it’s rather old. I know nothing about watches though, like what is a jewel?

The person who gave it to me says it looks exactly like a Lady Rolex, but I don’t even know what they look like either, sooo… I just need a battery. And I’d really like to loosen the band by one tiny piece of gold wristband. Is that possible? I stopped by walmart tonight to see if they would sell me a battery but they told me they can’t take the backs off watches anymore, and the size number is inside.

Mine says SEIKO 3Y03-0160 A4, water resistant, Japan M, base metal st. steel back. Does that tell you about what year mine was born? 😉 Also on front it has the day and date.
What is the best tool to open the back with? They let me use their tiny screwdriver set at Walmart but I don’t see how that could work. not for me anyway.

Any help that you can provide would be just awesome for me!
Thank you sooooo much for this cool message board! You’re the best!

how did that ugly avatar get on my post? i hate the color pink, ugh, can it please be changed? help? thanks!

hell0 quartzimodo,

the watch serial number is 114644. so are you saying that i won’t be able to tell if it was made in January of 2001? or 1991? or 1981, etc? and does it matter which year it was made when purchasing a battery for it?

do you recommend a place online to find correct batteries for certain watches? i would buy quite a few for different dead watches I have, if so.

thanks for passing along the excellent advice and experiential knowledge on this subject

Dear Quartzimodo,

I’m Mongkol from Thailand. I has 1 Seiko 5 Sports, Could you please help me to know this watch is original one or replica.

Serial number 230116
7S36-03D0 AO(in square) KY

and have litle card with watch
Cal.7S36, Automatic
Barcode 4954628101266

Thank you for your support in the future


Sawadee, Mongkol

This is a good question. As far as I know there are no fake Seiko models made like the new SNZF45K with the present 7s36C movement. Therefore your Seiko 5 Sports watch would be a genuine one.

It’s made on March 2012 and the SNZF45K is a very recent model.


Dear Quartzimodo,

I’m Mongkol again. I saw half circle (inside) it have 3 line


Thank you again


I bought both a ladies Seiko solar and a gents Seiko 5 glass back watch in Dubai last week. The sales assistant wrote the serial numbers on the guarantee but did not say which is for which watch.
The numbers she wrote are PO22PI and KK6211. These do not appear to be serial numbers !!!… Could they be the model numbers?
The number on the ladies watch appears to be 1N1298.
I cannot read the serial number on the gents watch as the bracelet blocks my view.
I am now home in Australia and cannot return to the shop in Dubai.
Can you help me determine which guarantee is for which watch ? Thankyou Valerie

I have a seiko mickey mouse ladies watch that was given to me in the 80’s. It has a two toned metal band, a white face, a date square. the serial number is3y030039 and the watch number is 960335. I dont still have the warranty papers, but I do remember that it was water resistant to a deep depth, like 100 ft or more. I sent it to be repaired to CSA and they tell me it is not high grade water resistant, but I have always worn it in water and it never leaked. They want $164 to repair it and don’t guarantee it to be worn while swimming. Is it worth the cost to repair? I found your site very informative.

im not sure if you got my question. Judy, about the Mickey Mouse ladies watch.

hi! i liked ur article my mom is big fan of vintage watches and she has a gold plated seiko pendant at the back the following numbers are written ASGP 21-7160 and 6900431 please i need ur help in knowing its re-sale value ! i would be really greatful for ur cooperation! its in best quality and still shiny and lustrous

hi! i liked your article very much im a great fan of collecting watches my mother has a seiko gold plated pendent watch and the numbers that are written at the back are these ASGP 21-7160 and 6900431 im unable to figure out the year of manufacturing is as the numbers are some what confusing please help me with this please i would be really grateful also if you can tell me its re-sale value that would be really nice!


it is very helpful for me, i can see it on my seiko chronograph 7t32-6m10, from your table, 6m10, it means 1996 May, and watch number 10, is that right ?

thanks very much


Hi Rudi,

It doesn’t work that way. 7T32 is the caliber type while 6M10 refers to the caseback model. You also need to know the six digit serial number, with the first two digits identifying the production year and month respectively.

Kindly go through my article again as you’ve sort of misunderstood my guide. 🙂