However, there are circumstances in which the calculator may give you inconclusive or erroneous results. Or no results at all. When that happens, I would resort to what I call "dead reckoning" or rough estimation.
Dead reckoning is similar to navigating your way at sea by orientating yourself with the heavenly objects like the sun, moon and the stars. You won't be accounting for wind conditions and at best your estimate may be a few miles off your actual position. That's when a GPS unit comes in handy!
Manually estimating the production date of a Seiko involves the element of anachronism. What is anachronism? Basically, it is the utilization of an event, a person, an object, language in a time when that event, person or object was not in existence. In other words, an anachronism is something that occurs out of its proper time. The chronological error of an anachronism can occur in either direction; it can result from something from the past being represented as if it belonged in the present, like an archaism, or it can result from presenting something at a time before it actually appeared, occurred, or existed.
And anachronism is the key to manually estimating the production date of your Seiko watch.
An example would be saying that a digital LCD watch was produced back in 1964 or claiming that old Kinetic watch in your drawer was purchased in 1983. Or an eBay seller proclaiming a vintage Seiko 7T59 quartz chronograph as a brand new model from 2003. In actuality, digital watches were only commercially available in the middle of the 1970s. Seiko Kinetics, originally branded as "Auto Quartz" and "A.G.S" (Automatic Generation System) only appeared at the end of the 1980s. As for the prized and short-lived, rare 7T59 chronograph models, they were only made between 1991 and 1993.
Putting it in another way, it's like saying the iPhone was already available in the 1990s or Microsoft Windows 7 users were running the operating system in 2004 (neither are true!). Eagle eyed movie buffs are quick to point out anachronisms in movies and you can read about them under the "Goofs" section for the movie title in the Internet Movie Database.
OK, now that you basically know what an anachronism is, let's learn how to date your Seiko watch manually!
To perform a dead reckoning dating of a Seiko watch, the five things that you need to know are:
History of the caliber
Reference number chronology
Signs of aging and wear
History of the caliber
Knowing when the caliber was first made and ended production would the first useful clue.
A very straightforward example is the 7002 automatic diver which was introduced in 1988 to replace the aging 6309 model whose production years ran from 1976 to 1988. The 7002 had a market life span of eight years and was shelved by mid 1996 (replaced by the current 7s26 caliber). Therefore all 7002s couldn't be made earlier than 1988 nor later than 1996.
The 7002-based SDS097K (left) and its successor model, the 7s26-powered SKX171K (right). Note that the 7002's crown position is at 4 o'clock and lacks a day calendar display. Pics courtesy of Chronograph.com
Another good instance would be the famous 6138 and 6139 automatic chronographs. Seiko introduced these robust and workhorse calibers in 1970 and 1969 respectively. Neither calibers never made it to 1980 and to my best knowledge, Seiko ceased making 6139s between 1978 and 1979.
Why were they discontinued? My guess is these calibers were getting more costly to manufacture and at the same time, Seiko wanted to push its quartz technology to the watch buying public. Maybe at the time they thought that mechanical chronographs were obsolete and quartz was the way to go.
The discontinuation of the 6138 and 6139 movements also unfortunately spelt the death of affordable Seiko automatic chronographs, much to the disappointment to Seiko mechanical watch fans. Currently, Seiko only offers automatic chronographs for its higher end lineups, such as the Brightz (caliber 6s28), Prospex Flightmaster (caliber 6s37) and the "Rolls Royce of Seikos" - the magnificent Seiko Credor (caliber 6s37).
An early 6138-0011 from Oct 1970 (left) and a late production 6138-0011 dating to Apr 1977 (right). Note the "waterproof" marking on the earlier watch's caseback and "water resistant" on the other one.
Complications in dating a Seiko watch will arise when production of the caliber hits 10 years or longer. Generally, Seiko doesn't continue making the same caliber for longer than 8 years unless the caliber itself is profitable to manufacture or it came up with a replacement caliber.
Take for example, the 7T32 alarm chronograph. It first debuted in 1988 and was discontinued sometime in 2002. Therefore, if the a 7T32's serial number starts with "1N", you could narrow it down between 1988 and 2002. It cannot be 1981 because this caliber wasn't available yet! Neither can it be 2008 because the caliber was already discontinued six years earlier.
This unfortunately leaves you with two possibilities - either November 1991 or November 2001. Obviously, this is not going to be very helpful because the correct year of production has to be either one of them but not both! Try to enter the caliber and the serial number into the Production Date Calculator and it will assume that the watch is from November 1991.
So how do you determine which is the correct production year? We take a step further by knowing the chronology of the watch's reference number.
Reference number chronology
When faced with the above dilemma, the next logical choice would be to know the chronological order of the model. This is not easy to tell unless you have seen photos of models of the same caliber to serve as reference.
Early Seiko 7T32s have reference numbers beginning with "SDW" and followed by three digits while the last 7T32 models ended with "SDWG" with two trailing digits. The digits start from the lowest order to the highest order. When Seiko runs out of reference numbers, they would append a new alphabet starting with the letter "A".
In this example, a 7T32 model with the reference prefix "SDW" obviously predates one with a "SDWA" prefix. In the same manner, a model that has the prefix "SDWF" would be a much later model than a "SDWB" and so on.
If you are able to determine that your mystery watch has a reference prefix e.g., "SDWF", you can be sure that your watch is a late model 7T32. Therefore your watch would be a November 2001 production and not from 1991.
Three 7T32s arranged in chronological order. The SDW379P (left) predates the SDWA65P (middle) while the latter in turn, predates the SDWC02P (right). Pics courtesy of Chronograph.com
The same model numbering convention holds true for other Seiko models. When the company dropped the 7T32 caliber in the early 2000s and replaced it with the 7T62, it designated the first batch of 7T62s as the SNA-series. As mentioned earlier, Seiko assigns a running prefix number for its new models until it runs out of numbers. Thereafter, it would append an additional character into the reference prefix, starting with the alphabet "A", as in "SNAA".
Six years have passed since first SNA models rolled out the factory assembly lines and at the time of writing, the most recent models have the "SNAB" prefix. In a few months from now, you'll find 7T62 models with reference letters starting with "SNAC" and perhaps, "SNAD". This will continue until Seiko decides to discontinue the 7T62 caliber and replace it with a new one. Its replacement caliber will of course, have different reference letters.
Two 7T62 alarm chronographs side-by-side: An early Seiko Sportura SNA137P (left) and a very recent model SNAB69P (right). Watch photos courtesy of Chronograph.com
When the watch's reference number is unknown, there are certain visible clues that can help you zero in the watch's production year. The key is in the watch markings. For instance, in the 70s and 80s Seiko typically uses the word "Seiko Quartz" or "SQ" to denote that the watch is a quartz powered model.
The 80s was particularly Seiko's golden age for their analog quartz models. In fact, the Japanese watch giant was capitalizing on its solid reputation as the world's largest producer of analog quartz timepieces. The words "Quartz" and "SQ" also served as a selling point and differentiated their quartz models from their automatic counterparts.
By the mid 1990s, Seiko had already carved itself a solid reputation as a quartz watch manufacturer. Seiko was churning out more quartz timepieces than mechanical ones and to the masses, a Seiko watch is generally associated with a quartz movement.
A beautiful and rare 2A22-026A Professional Diver's 200m. The "Quartz" and "SQ" markings on the dial and bracelet clasp respectively are visible clues that this watch was from the mid 80s, Pictures courtesy of Thian Wong.
Seiko probably felt they longer needed to mark their quartz products with the words "Quartz" and "SQ" so both labels were eventually dropped. Since the mid 1990s, all Seiko watches are generally quartz by default. There are also some exceptions to this rule. For instance, the SHC015P and SHC033P divers are still marked as "Seiko Quartz" for certain export markets. I presume the Seiko company did this to distinguish them from their 7s26 automatic divers as both models have strong resemblances to their automatic counterparts.
Currently, all Seiko watches are quartz models except if the movement type is indicated on the dial. Therefore, if the dial doesn't say "Automatic", "Kinetic", "Thermic", "Solar", "Direct Drive" or "Spring Drive" then you can be sure that the watch is battery-powered quartz. This applies to all current Seikos, from their most affordable generic quartz watches to the high end Grand Seikos.
Some vintage quartz divers come with battery change year markings on their casebacks. If the watch caliber's battery life is rated for five years, there should be an indentation mark to indicate the approximate next battery change.
This information can be very useful in getting the watch's production year right. The photo below shows a vintage 7C43-6020 Professional Diver's 200m. You can see the battery change markings on the caseback ranging from 1995 to 2004. The dimple mark is stamped on the year "95" as the 7C43's battery life averages 3 years.
An equally gorgeous and rare Japan market, Professional 200m diver's watch made in 1992. Photo courtesy of Ty Maitland.
As with fashion, hairstyles, music and popular culture, watches also undergo design trends and fads. Getting the production year right purely based on the watch design is not that easy but you can still make educated guesses if you know a thing or two about design elements in its time.
For instance, LCD watches were the craze in the mid 1970s and Seiko produced pretty good classic LCD timepieces during the era.
Therefore if you have Seiko watches looking like in this picture below, there's the element of certainty that they were from the late 1970s to the early 80s and no later than that.
A trio of well preserved Seiko LC digitals from the 70s. Seiko gradually phased out LCD watches with metal cases and bracelets by the mid 1980s.
Throughout the 1980s, Seiko made quite a number of analog-digital quartz calibers. The analog-digital trend unfortunately also faded by the early 1990s in favor of full analog quartz designs. Currently Seiko has only two analog-digital calibers left in its stable - the world-time H023, which is nearing its end of production life and also its latest H024 caliber.
If your watches look like these, you can be sure that they were from the 1980s.
A memorable example is the "moonphase" display trend on watches in the late 1980s. Practically almost all manufacturers (even the Guess fashion brand) had moonphase dial watches back then.
The moonphase fad had died down by the late 90s and to my best knowledge, currently only Citizen has moonphase models in their upmarket quartz and Eco-Drive Campanola line and of course, a handful of fine Swiss mechanical watches.
Two examples of forgotten moonphase Seikos from the early 1990s - a 7F39 (left) and a 7A48 (right). Seiko no longer made moonphase quartz watches since then.
As Seiko has made countless models since the last century, it is not possible to detail every possible style in this article. However you can at least scope the production year within one decade if you're familiar with the watch styling.
As with other brands, Seiko watches also undergoes many stylistic changes over the decades. You could also browse through Jayhawk's Watch Database and see if your watch or a model like it is listed there. Here are some additional tips that you may find useful:
A watch marked as "Seikosha" instead of Seiko is likely to made in the early 1960s or earlier.
A Seiko that has a 7-digit serial number is likely to be made in 1968 or earlier.
A Seiko that's marked as "waterproof" is likely to be made before mid 1971.
A Seiko that uses Promethium-147 or Tritium radioactive luminous compound (instead of the non-radioactive LumiBrite) is likely to be made before the mid 1990s.
A Kinetic Seiko that's labeled as "AGS" or "Auto Quartz" is likely to be from 1996 or earlier.
A Seiko 5 with a solid stainless steel caseback (as opposed to glass display back) is likely to be made well before 2004.
Some Seiko 7s26 divers, like the SKX011K were introduced earlier but were later dropped from the market and replaced with the SKX011J. In most likelihood, an SKX011K predates the SKX011J version.
Signs of aging and wear
Although estimating the production year of a Seiko watch could be done by looking for signs of aging, wear and tear, this is a very subjective and by no means a foolproof method for determining its age.
Generally, a ten year old watch or older would show telltale signs of its age in the form of case scuffs, dents, scratches on the glass and bracelet, non-working functions, faded dials, rusty watch hands, casebacks, etc. On the other hand, a relatively new watch could also accumulate those scratches, dents and cosmetic flaws, depending on the manner the previous owner wore his timepiece.
One way is to judge the condition of the dial. Watches that have lived a long rough life have a tendency to have faded dials and bezels, especially if the dial has been exposed to the sun daily for years. It's not just the heat but the sun's ultraviolet (UV) rays that will cause dial fading.
Here's an example of an old SKX025J that predates the SKX025K that is sold today. The watch is non-functional and the eBay sellers sold this as a parts watch.
An early model Japan-made, SKX025J mid-sized diver. This watch was probably made between 1996 and 2001.
Manually tracing the production year of a Seiko watch can be very tricky at best. If you have a relatively little known caliber or model you may be forced to resort to estimating by the watch design and text markings.
If all fails, post a question in the Seiko & Citizen Watch Forum as there will be a few kind and helpful members who may recognize the caliber or watch model.
Related article(s): How To Tell When Your Seiko Was Made (Part 1)
Originally posted 2008-07-16 20:29:46.