SEIKO, 2010 Spring Drive Collection

Seiko - History of Spring Drive

SEIKO watches, the Ananta watch manufacture (the insides)

Does the Spring a Mechanical Make? by Ken Worley

Does the Spring a Mechanical Make?

All photos Copyright Ken Worley

There has been some lively debate from time to time about the "status" of Seiko's Spring Drive movement. Is it a quartz movement? Is it mechanical? Although I know I love the movement, it has taken a while to decide exactly why. If you're interested, I thought I'd share some of my thoughts in this essay.

Do We Love Watches?

Is it the watches we love, or is it their movements? That can be a difficult question. For those of us who love mechanical watches, I believe it is the movement that is the essence of the watch. It is the movement that makes it special. To gaze into the workings of a mechanical movement and see this tiny machine working, spinning and ticking fills me with a sense of wonder. How could it be that a tiny balance wheel, flying back and forth against its spring, can regulate the unwinding of the mainspring so accurately? It is truly amazing. To me, the love of such a magical thing is obvious, self-evident; how could you not love it?

Omega Speedmaster Professional with display back

Quartz watch proponents know the answer, but let me guess at it. To a person that does not understand or appreciate the magic of a mechanical watch movement, a watch is a practical tool. It is merely a convenient means of checking the time. All notions of jewelry aside, a watch should be as accurate as possible and as inexpensive as possible. Okay, sure, style plays a role as does prestige. But with quartz watches, the notion of timekeeping seems to exist separately from the watch as jewelry. It takes on a secondary role. It is taken for granted. "Why, what a lovely diamond encrusted bracelet that is…and it also tells time." In other words, quartz watches are loved for the attributes of the movement: accuracy, battery life, and functions, as well as for the style of the watch, not for the movement itself.

I know there are many people who love both quartz and mechanical. But, if I may postulate, they are loved for different reasons. How could a mechanical watch be loved for its true practicality? It is less accurate and more expensive than a quartz watch of equivalent build quality. How can a quartz watch be loved for the wonder of its movement? Looking into a quartz movement is like staring at a battery. I've seen quartz watches with display backs and I can't fathom the reason. It's beyond me.

Let me also make it clear that I know there are many other reasons to love a watch regardless of its movement. Watches can hold tremendous sentimental value (just watch Pulp Fiction). They can be loved for their pure style, or for their history. There are other reasons as well, but they're all outside the scope of this essay. My thoughts are centered around what's inside.

Let me also say that accuracy varies wildly in both mechanical and quartz watches. Some mechanical watches are very accurate while some quartz watches leave much to be desired, keeping time much less accurately than a good mechanical. Quartz watches, however, are certainly capable of much more accuracy than any mechanical watch and there are many examples which prove it. I don't think many people would argue with the assertion that, on average, quartz watches are more accurate than mechanical watches.

Ups and Downs

Let me summarize briefly what I consider to be the pros and cons of each type of watch (and I know I'll leave some things out). I purposely leave out any notion of whether a watch gets you noticed (pro or con), and it's true that these are generalizations.

Mechanical:

+ Amazing, magical tiny machine

+ Cool sweeping second hand (no once-per-second tick)

+ Requires no batteries

- Requires servicing from time to time

- Requires winding (either by being worn or manually)

- Expensive (compared to most quartz)

Zenith Rainbow Flyback

Roamer La Grande

Minerva Palladio

Quartz:

+ Usually highly accurate (a technological wonder)

+ Service required rarely (if at all)

+ Less expensive

- Movement is mundane

- Requires battery changes (rechargeables less so, but all rechargeable batteries die)

- Annoying once-per-second tick (okay, maybe only for me)

Breitling B-1

Omega Speedmaster Professional X-33

Wenger Commando

What is Mechanical? What is Quartz?

I've been throwing around the term "quartz watch" quite recklessly. For me, it has a very specific meaning: a watch that runs off battery power (whether disposable or rechargeable) and which moves the watch hands by means of one or more stepper motors. I know that everyone does not share this definition, but for me "quartz watch" is equivalent to "battery powered watch" for I don't know of any battery powered watch (currently manufactured) which does not use a stepper motor. So, to me, a battery powered watch is, more or less, just a tool for telling time. I have several that I like and I do like a certain look. I'm even willing to spend a fair amount of money for just the right look, but I know I'm buying a look. I'm not buying magic.

Perhaps I've also been using the term "mechanical watch" a little too carelessly. After all, anything that has parts and locomotion of some sort is in a sense mechanical, yes? My definition of a mechanical watch, and I know almost everyone will agree with me at least to some extent, is one which contains a mainspring whose power is used to drive the watch hands. It contains no battery and no stepper motor. That sounds fairly self-evident, doesn't it? And yet, it leaves out the thing that some people consider to be essential to a mechanical watch. Here's where we may diverge. Does a mechanical watch have to have a traditional escapement?

It's Not So Black and White

As it turns out, it is difficult to define, at least for everyone, what is a quartz watch or what is a mechanical watch. I've given you my definitions, but there really aren't just two black and white categories. There have been several mixtures of the two technologies in an attempt to capture just the right mix of mechanical wonder and quartz accuracy and practicality. Many of these are still in use. Here are the major contenders:

Tuning Fork:

These appeared at the beginning of the battery powered watch era. The movement uses a battery to power a "tuning fork" which vibrates at around 300 times per second. The motion of the tuning fork itself drove a tiny gear whose power was transmitted to the hands. These movements, made famous by Bulova with their Accutron models, were a revelation. They were more accurate than most mechanical movements and displayed a smoothly sweeping second hand which "ticked" faster than the eye could see. Quartz technology, however, quickly drove tuning forks out with even higher accuracy and longer battery life. Tuning fork movements are no longer produced.

Standard Quartz:

We've discussed this one already. A quartz watch uses a battery to power a quartz oscillator which vibrates at a fairly stable rate around 32,000 times per second. Its vibration is used as a reference rate to drive the watch hands using a stepper motor.

Mecaquartz:

A mecaquartz is a battery powered watch which keeps time using a quartz crystal oscillator and moves the hands using a stepper motor. The difference between this and a regular quartz watch is that the watch includes a mechanical chronograph module. The watch generally uses a stepper motor with a higher step rate to drive the mechanical chronograph so that it looks the same as the chronograph you would see on a mechanical watch - generally stepping four or five times per second. Most battery powered chronographs simply use several stepper motors to drive the different chronograph hands.

I owned a Breitling Chronoracer Rattrapante mecaquartz watch at one time. It was a beautiful watch, and I appreciated the mechanical chronograph especially with the split-second feature. In the end, however, I thought of it as basically a quartz watch. It had a battery that would have to be changed and the standard second hand ticked once per second like any other quartz watch. It seemed to be a combination of more cons than pros. It retained the battery powered stepper motor that I have no love for from the quartz side, while adding the extra service requirements and expense of a mechanical chronograph movement. I still thought it was a nice watch, but more for its style and accuracy than for its movement. It wasn't my "perfect" watch by any stretch.

Breitling Chronoracer Rattrapante (mecaquartz movement)

Kinetic:

A kinetic movement (this is just Seiko's term for the technology) is a like a standard quartz watch except that it uses a rechargeable battery or capacitor. I know of at least two companies that produce such a movement: Seiko and Ventura. These have a rotor, just like an automatic mechanical movement, which is used to drive a small generator circuit which recharges the battery. Some of these watches have a display back so you can watch the rotor spin.

To me, kinetic movements are a bad trade-off. You remove the necessity to change the battery every couple of years, but you add a great deal of inconvenience when the rechargeable battery does finally give out. And believe me, every rechargeable battery does give out eventually. Perhaps it wouldn't be until after the practical life of the watch is over, but judging by reports I've seen on the internet, this is certainly not guaranteed to be the case. Scientific, I know.

This movement also introduces one of the disadvantages of a mechanical movement to quartz: that the watch be worn in order to work the rotor and recharge the battery. They generally hold quite a charge and may not require any recharging for months, but the requirement is still there. You may not be able to set it in a drawer for a year, then put it right back on with no further adjustment like you can with most quartz watches.

Solar:

A solar movement is like any other battery powered quartz movement except that it uses solar energy to charge a rechargeable battery.

Just as the kinetic movement, this one trades the inconvenience of a battery change every couple years for the larger inconvenience at some later time when the rechargeable battery gives out. It also introduces the (not so difficult) requirement that the watch be exposed to light at least some of the time. If you wear it all the time or even a fair amount of time, this is not a problem. Even if you just leave it out on top of your dresser, it will likely hold a charge nicely. You just can't put it away for a year in a drawer and expect it to be charged when it emerges.

In my opinion, this is a much more efficient way to maintain a rechargeable battery than the kinetic. They hold their charge well, don't require that much light to charge, and don't have the additional complexity of a moving rotor. They can also charge without being worn (and without a watch winder) by simply being left out in the light.

Radio Controlled:

A "radio controlled" watch movement is a standard quartz movement which receives a radio time signal from an atomic clock source (like the one in Boulder, Colorado in the US). They are not so much accurate as often corrected to exactly the right time.

And Then We Have The Spring Drive

All currently produced, battery powered wristwatches are quartz based. That is, at their base, they are powered by a battery and use a stepper motor to drive the mechanism. Seiko's Spring Drive approaches from the opposite direction. Beginning with a mechanical movement, using a mainspring to drive the mechanism, the Spring Drive replaces only the escapement - the mechanism that regulates the rate at which the mainspring unwinds. Instead of a traditional escape wheel and balance spring, the movement generates electrical energy as it unwinds. This is used to power a quartz oscillator and an electromagnetic brake which keeps the "glide wheel" spinning at exactly 8 revolutions per second in a smooth motion.

Arguably, this movement combines the special nature of a mechanical movement with the higher accuracy of a quartz movement. It retains the wonder of a tiny mechanical machine spinning and whirring using only the power of its mainspring while, at the same time, adding the accuracy of quartz and some of the lower maintenance requirements of quartz movements due to decreased friction and a single direction of motion. It also adds its own special perk to those who might appreciate it: a perfectly smooth non-ticking second hand. It's the furthest you can get from the once-per-second tick tick tick of a run-of-the-mill quartz movement.

Seiko manufactures Spring Drive movements to the highest build quality using more parts than most traditional mechanical watches. Fewer than 10 highly skilled watchmakers at Seiko are qualified to assemble and work on the movements. No other company makes anything remotely similar.

I have owned two watches containing a Spring Drive movement (the second I still own). The first was a Seiko Marinemaster 600m Spring Drive. It was a huge chunk of a diver watch and a model sold only in Japan. The second is a Seiko Spring Drive GMT which contains the same movement as the Marinemaster and also sports a display back that lets you see the mainspring unwind via the spinning glide wheel. This model is part of Seiko's international line of Spring Drive models available around the world. Both displayed amazing accuracy varying by less than a second per month from the atomic clock.

Seiko Marinemaster 600m Spring Drive

Seiko Spring Drive GMT

What makes a movement special?

There are many people who dismiss Seiko as a maker of mass market quartz watches. Perhaps they blame Seiko, as the inventor of the quartz watch, for the temporary demise of the mechanical watch industry in the "dark years." For some, "Swiss Made" is what makes a watch good as gold. But wait, that Panerai sure is nice. Guess we'll have to include Italian watches too. Oooh, I like that Glashutte Original. Okay, Germany is in. Perhaps any movement made in Europe is okay?

Ask a group of watch aficionados what makes a mechanical movement really special and I think you'll get several common answers (among others):

- High build quality (and, sometimes, decoration)

- High complexity (complicated or complex to build)

- Exclusivity (usually to one brand i.e. "manufacture" but not always)

- History & Tradition (of the company)

These are the traits that make a high dollar Swiss (or Italian or German) watch worth the money. Things don't always add up though. Some brands that are highly respected and make expensive watches do not use exclusive movements. Some of them don't have a long history (although they may have assumed a name that is steeped in history and tradition). Many fine mechanical watches use relatively pedestrian movements made by ETA and that's okay. But everything does add up for Seiko. It meets all of these conditions with the Spring Drive (as well as with some of its other high end mechanical movements). Seiko has a long history of tradition and innovation in watchmaking. These movements are of extremely high build quality and are built by Seiko exclusively for use in their own watches. The Spring Drive, in particular, is highly complex requiring many years of research and prototyping to perfect.

For those that do still think of Seiko as only a mass market quartz watch pusher despite this, I guess I have to chalk that up to guilt by association. Seiko does produce a lot of quartz watches which, while generally more expensive than most quartz watches, are a lot less expensive than most mechanical watches. I guess this leaves them in the same situation as many other companies who have chosen to use the same brand name for products intended for a broad market as well as those intended for a much more exclusive market. Alas, the Ford GT will forever be associated with the Ford Fiesta! :)

So where does this leave me?

I have owned several mechanical watches, including at least one which was even more accurate than some of the quartz watches I own. My Breitling Navitimer Montbrillant Datora ran, for the most part, dead on for the relatively short time that I owned it. I only gave it up to get a Spring Drive. I lust after mechanical watches with all their little gears, their mainsprings, their mechanical whirrings. And yet, at the same time, I'm an accuracy freak. I almost (note that I said almost :) cannot stand to wear a watch that needs to be reset every few days or every week to keep it within a reasonable interval from the atomic clock. I start to get antsy when my watch reads more than 5 seconds off of the "real" time. I know this is just a personality quirk on my part, but it is there nonetheless and I know I'm not alone. For some of us, accuracy is important.

Breitling Montbrillant Datora

At the top of my list of desirable watch traits are mechanical and accurate while at the bottom are the requirements for battery replacement and regular service. And at the very bottom of my list is whether or not everyone agrees with me. This leaves, at the top of my list, the Seiko Spring Drive.

Seiko Spring Drive GMT

Seiko Spring Drive GMT

Seiko Spring Drive GMT display back

Hope you enjoyed my ramblings,

Ken

Calibres Seiko

Movt. #	Prefix #	Winding	Model Name	Model #	Jewels	Made Year	Made Loc.	Diam; Thick	Beats/sec
10	A	Hand	10Solar	10S	19		D	15.5 x 13; 3.5t	5.5
10	B, C	Hand	10Solar	10S	17 - 21			15.5 x 13; 3.5t	5.5
10	M	Hand	10Solar	10S	17			15.5 x 13; 3.5t	5.5
10	04A,B	Hand	10Angel	10AN	21			15.5 x 13; 4.4t	5.5
10	04C	Hand	10Angel	10AN	17 - 21			15.5 x 13; 4.4t	5.5
10	04D,M	Hand	10Angel	10AN	17			15.5 x 13; 4.4t	5.5
10	20A,B,C	Hand	10QueenSeiko	10QS	23	1964	D	15.5 x 13; 3.5t	5.5
10	40A	Hand	10Solar Special	10SL	23			15.5 x 13; 3.5t	5.5
11	A	Hand	11Solar	10S	17 - 21
11	04A	Hand	Salvia	SV	17 - 21			15.5 x 13; 4.4t	5.5
11	20A	Hand	11Queen Seiko	11QS	23	1970	D	15.5 x 13; 3.5t	6
11	20A	Hand	Belfina/11Queen Seiko Special	11QSL	23
11	40A	Hand	11 Solar Special	11SL	23
11	44A	Hand	Salvia Special	SVL	23
15	A	Hand	Lady Seiko	LS	21	1959	D	19.6 x 12.9; 3.5t	6
15	20A	Hand	Fine Seiko	FS	17			19.8 x 9.6; 3.5t	5.5
15	20B	Hand	Fine Seiko	FS	17 - 23
17	A	Hand	Seiko1700	1700	17			∅13.5; 3.2t	6
17	A	Hand	17Queen Seiko	17QS	17
17	A	Hand	17Queen Seiko Special/17 Belfina	17QSL	20	1969	D
175		Hand	Sportsman		15	1960	S
18	A	Hand	Universe	UN	21	1960	D	∅13.5; 3.0t	5.5
18	B,M	Hand	Universe	UN	17
19	A	Hand	Venus	VE	17	1960	D	19.6 x 12.9; 3.5t	6
19	04A	Hand	19Venus	19VE	17 - 23			19.6 x 12.9; 3.5t	8
19	20A	Hand	Venus Special	VEL	21
19	44A,B	Hand	Seiko High Beat Chronometer 36000	1944
19	44B	Hand	Seiko High Beat Chronometer	19CM	23	1967	D	19.6 x 12.9; 4.4t	10
19	64A	Hand	19 Grand Seiko	19GS	23	1968	D	19.6 x 12.9; 4.4t	10
19	84A	Hand	19 Grand Seiko High Beat V.F.A.	1984	23	1972	D	19.6 x 12.9; 4.4t	10
205		Hand	Harmony	HA	19	1961	S
21	A,C	Hand	Sports Lady 17	SLS	17	1961	D	17.8 x 15.3; 3.5t	5.5
21	D	Hand	Sports Lady 17	SLS	17
21	02A,C	Hand	Sports Lady 17 Calendar	SLSC	17
21	04A,B	Hand	Chorus	CR	17	1961	D	17.8 x 15.3; 4.4t	5.5
21	05A	Auto	Matic Lady Calendar	MALC	21
21	07A	Hand	Chorus Calendar	CRC	17 - 21
21	07B	Hand	Chorus Calendar	CRC	17 - 21 - 23
21	17A	Hand	Chorus Calendar	CRC	17
21	18A	Hand	21 Chorus Calendar	21CRQ	17 - 21 - 23
21	19A,B	Hand	Chorus Weekdater	CRW	21
21	40A	Hand	Seiko 2140	2140	21
21	60A	Hand	School Time	21ST	17
22	01A	Auto	Seiko 2201	2201	17
22	02A	Hand	22 Chorus Calendar Echo	22CRE	17 - 21
22	02A	Hand	22 Chorus Calendar Special	22CCL	23
22	05A	Auto	22 Matic Lady Calendar	22NLQ	17 - 21	1970	D	∅17.2; 5.7t	8
22	05A	Auto	22 Matic Lady Calendar Special	22MSL	25
22	06A	Auto	22 Matic Lady Weekdater	22MLW	17 - 23
22	06A	Auto	22 Automatic Weekdater	22ATW	17 - 23
22	20A	Hand	Seiko 2220	2220	17 - 24
22	42A	Hand	22 Chronometer	22CM	23	1971	D	∅17.5; 5.8t	8
22	45A	Auto	22 Automatic Chronometer Calendar	22ACM	25
24	06A	Hand	2Matic Lady Weekdater	24MLW	23
24	09A	Hand	Seiko 2409	2409	23
24	11A	Hand	Seiko 2411 ECharriot	2411	23	1972	D
24	15A	Hand	Seiko 2415	2415	23
24	18A	Hand	Seiko 2418	2418	23
24	19A	Hand	Seiko 2419	2419	23
24	21A	Hand	Joyfull Special	2421	23
24	26A	Hand	Joyfull Special	2426	23
24	31A	Hand	Bellfina Seiko 2431	2431	25
24	25A	Hand	Bellfina Seiko 2435	2435	25
245		Auto	Sportsmatic	SMA	17 - 19	1961	S
2451		Auto	Sportsmatic	SMA	17 - 19
24	66A	Auto	Joyfull Special	2466	25	1974	D	∅19.4; 4.3t	8
25	01A,B,C	Auto	25 Seikomatic Lady	25MAL	17	1965	D	∅17.5; 5.3t	5.5
25	02A	Hand	Chorus Calendar Special	CRCL	17 - 23	1964	D	∅17.5; 5.5t	5.5
25	05A,B	Auto	25 Seikomatic Lady Calendar	25MLC	21
25	15B	Hand			17
25	16B	Auto			21
25	17A,B	Auto	25Seikomatic Lady Calendar	25MLQ	17 - 21	1965	D
25	18A,B	Hand	25 Chorus Calendar Special	25CCL	23
25	18B	Hand	25 Chorus Calendar Echo	25CRE	17 - 21
25	19A,B	Hand	25 Queen Seiko 2519	2519	23	1965	D	∅17.5; 3.2t	5.5
25	39A	Hand	25 Queen Seiko Special	2539	25	1966	D	∅17.5; 3.2t	5.5
25	59A	Hand	25 Queen Seiko High Beat	2559	24	1968	D		8
25	65A	Auto	25 Seikomatic Special	25MSL	25
270		Auto	Maticlady		21	1960	S	18.4 x 15.3; 5.7t	5.5
27	06A	Auto	27 Maticlady Weekdater	27 MLW	17 - 21	1970	D	∅17.5; 5.7t	8
290		Hand	Gyro Marvel	GM	17	1959	S
2906		Hand	Joyfull		17 (21)	1976	D	∅18.4; 5.3t	8
3140		Hand	Seikoliner		21	1960	S
3180		Hand	Grand Seiko (first model)	GS	25	1960	S
330		Hand	Queen Seiko		23	1962	D	18.4 x 15.3; 3.5t	5.5
341		Hand	Crown Special	CWL	23	1961	S
375		Hand	Disney Time		7	1961	S
394		Auto	Seikomatic Selfdater	MAS	24	1962	S
395		Auto	Seikomatic Selfdater Quick Set	MASK	24
400		Auto	Matic Weekdater	MAW	33
40	05A	Auto	Seiko Bellmatic Calendar	40BC	27
40	06A	Auto	Seiko Bellmatic Weekdater/Business Bell	40BW	17 - 27	1967	S	∅31.2; 7.1t	5.5
402		Hand	Skyliner	SLN	21	1961	S
410		Auto	Sportsmatic 5	SMA5	21	1963	S
430		Hand	Grand Seiko Weekdater	GSS	35	1963	S
436		Hand	Sportsman 17	SMS	17	1960	S
4361		Hand	Sportsman 17	SMS	17	1960	S
44	A	Hand	44 King Seiko Quick Set	KSK	25	1964	D	∅26.0; 4.4t	5
44	02	Hand	44 King Seiko Calendar	KSSK	25	1965	D	∅26.0; 4.8t	5
44	20A	Hand	44 Grand Seiko/44 King Seiko Chronometer	44GS - EKSCM	27	1964	D	∅26.0; 4.4t	5
44	20B	Hand	44 Grand Seiko/44 King Seiko Chronometer	44GS - EKSCM	27	1964	D
45	00A	Hand	45 King Seiko	45KS	25		D	∅27.4; 3.65t	10
45	00A	Hand	45 King Seiko Chronometer	45KM	25			∅27.4; 3.65t	10
45	02A	Hand	45 King Seiko Calendar	45KSC	25	1969	D	∅27.4; 3.65t	10
45	02A	hand	45 Grand Seiko Observatory Chronometer	45KCM	25			∅27.4; 3.65t	10
45	20A	Hand	45 Grand Seiko V.F.A.	45GS	25	1968	D
45	22A	Hand	45 Grand Seiko Calendar	45GSC	25	1968	D	∅27.4; 3.6t	10
45	80A	Hand	45 Grand Seiko V.F.A.	4580	25	1969	D	∅27.4; 3.65t	10
45	82A	Hand	45 Grand Seiko Neuchatel Observatory Chronometer	45GSN	25	1969	D	∅27.4; 3.65t	10
460		Hand	Liner Chronometer	LNCM	25	1963	S
4S		Auto	Revised Cal. 52			1992	D
50	00	Hand	Tomony		7	1970	S	26.0 x 25.5; 4.4t	6
50	02	Hand	Tomony School with Date		7	1970	S	26.0 x 25.5; 4.8t	6
50	05	Auto	Tomony Automatic		7	1970	S	26.0 x 25.5; 6.4t	6
50	18	Hand	Tomony Seagull Digital Display		7	1974	S	26.0 x 25.5; 5.9t	6
50	C	Hand	Disney Time		17	1973	S
51	05							∅26.0; 4.9t	5.5
51	06A	Auto	51 Matic Weekdater	51MW	33	1967	D	∅26.0; 4.9t	5.5
51	25							∅26.0; 5.3t	5.5
51	26A	Auto	51 Seiko 5 (DX)	51-5	23	1967	D	∅26.0; 5.3t	5.5
51	39A	Auto	51 Seiko 5 (DX)	51-5D	27		D	∅26.0; 5.3t	5.5
51	45							∅26.0; 5.3t	8
51	46A	Auto	51 Seiko Pressmatic Weekdater	51PMW	27 - 30	1969	D	∅26.0; 5.3t	8
52	05							∅26.0; 3.9t	8
52	06A	Auto	52 Loadmatic Special Weekdater	52LMW	23 - 25	1969	D	∅26.0; 3.9t	8
52	16A	Auto	52 Loadmatic Special Weekdater	52 LWL	23 - 25
52	45A	Auto	52 King Seiko Chronometer (Calendar)	52KCM	25	1971	D	∅26.0; 3.9t	8
52	46A	Auto	Seiko Vanac	52KWL	25	1973	D	∅26.0; 3.9t	8
52	46A	Auto	52 King Seiko Chronometer Weekdater	52KWM	25	1971	D	∅26.0; 3.9t	8
52	56A	Auto	Seiko Vanac	52KWL	25	1973	D	∅26.0; 4.2t	8
54	A	Hand	Chronos	C	17 - 21 - 23	1958	D	∅26.0; 4.0t	5
560		Hand	Crown	CW	19 - 21	1959	S
56	01A	Auto	56 Loadmatic	56LMA	23	1968	S
56	05A	Auto	56 Loadmatic Calendar	56LMC	25			∅26.0; 4.3t	6
56	06A	Auto	56 Loadmatic Weekdater	56LMW	23 - 25	1968	S	∅26.0; 4.3t	6
56	19A	Auto	56 Seiko Duotime	56DMC	25			∅26.0; 4.2t	6
56	21A,B	Auto	56 King Seiko	56KA	25	1969	S
56	25A,B	Auto	56 King Seiko Calendar	56KAC	25	1968	S	∅26.0; 4.5t	8
56	26A,B	Auto	56 King Seiko Chronometer (Calendar)	56KCM	25	1968	S	∅26.0; 4.5t	8
56	26A,B	Auto	56 King Seiko Weekdater	56KAW	25	1969	S	∅26.0; 4.5t	8
56	21A,B	Auto	56 King Seiko Chronometer Weekdater	56KWM
56	26B	Auto	Seiko Vanac	56KAW
56	41A	Auto	56 Grand Seiko	56GA	25
56	45A	Auto	56 Grand Seiko (Calendar)	56GAC	25	1970	S	∅26.0; 4.5t	8
56	46A	Auto	56 Grand Seiko Weekdater	56 GAW	25	1970	S	∅26.0; 4.5t	8
57	B	Hand	Crown	CW	21			∅28.0; 4.7t	5
57	17A	Hand	Crown Chronometer (Calendar)	CWCGC	21	1964	S	∅28.0; 6.1t	5
57	18A	Hand	Countgraph (Olympic LE)		21	1964	S	∅28.0; 7.3t	5
57	19A	Hand	Crown Chronograph	CWCG	21	1964	S	∅28.0; 6.1t	5
57	20A	Hand	Grand Seiko	GS	25	1960	S	∅28.0; 4.4t	5
57	22A	Hand	Grand Seiko Selfdater	GSS	35	1963	S	∅28.0; 4.7t	5
57	22A,B	Hand	Grand Seiko Calendar	57GSC	35	1963	S	∅28.0; 4.7t	5.5
57	40A	Hand	57 Load Marvel (Engraved Numerals)	LMK	23	1964	S	∅28.0; 4.4t	5
57	40B	Hand	57 Load Marvel (Applied Seiko Logo)	LMK	23		S	∅28.0; 4.4t	5
57	40C	Hand	57 Load Marvel 36000	LM36	23	1967	S	∅28.0; 4.4t	10
57	60	Hand	Crown Special	CWL	23	1961	S	∅28.0; 4.4t	5
57	80	Hand	Skeletonized Watch		19	1981	S	∅28.6; 4.1t	6
57	A	Hand	Crown Selfdater		21	1961	S
603		Auto	Seikomatic	MA	17 - 20 - 21 - 30	1963	S
60	M	Hand	Gold Feather	GF	17 - 25	1960	D	∅27.0; 2.9t	5
61	A	Hand	61 Skyliner	61SLN	17 - 21	1968	S	∅27.4; 3.5t	6
61	02A	Hand	61 Skyliner (Calendar)	61SLC	17 - 21
61	05A	Auto	61 Diver (150m)	61MC	17	1968	S	∅27.4; 5.1t	5
61	05B	Auto	Seiko Diver (Hack Second)	61MC	17			∅27.4; 5.1t	5
61	06A	Auto	61 Seiko 5DX	61-5D	25	1967	S	∅27.4; 5.1t	5
61	06B	Auto	61 Seiko 5DX	61-5D	17 - 25	1967	S
61	06C	Auto	61 Five Actus	61-5A	17 - 23 - 25	1967	S
61	06C	Auto	Seiko Advan	61AD	17 - 23 - 25	1967	S
61	10A	Hand	61 Railroad Watch	61RW	21	1971	S	∅27.4; 3.5t	6
61	17A,B	Auto	61 Worldtime	61WT	17	1968	S	∅27.4; 5.1t	6
61	17A	Auto	61 Navigator Timer	61NT	17			∅27.4; 5.1t	6
61	19A,B,C	Auto	6Seiko 5 Sports	61-5	21	1970	S	∅27.4; 5.1t	5
61	38A,B	Auto	Seiko 5 Sports Speedtimer	61SPH	21	1970	S
61	38A,B	Auto	Seiko Chronograph	61CHW	23			∅27.4; 7.9t	6
61	39B	Auto	Fine Sports Speedtimer	61SPM	17	1969	S	∅27.4; 7.1t	6
61	39B	Auto	Fine Sports Speedtimer	61SPM	21	1969	S	∅27.4; 6.5t	6
61	45A	Auto	61 Grand Seiko Calendar	61GAC	25	1968	S	∅27.4; 5.6t	10
61	46A	Auto	61 Grand Seiko Weekdater	61GAW	25	1968	S	∅27.4; 5.6t	10
61	55A	Auto	61 Grand Seiko Special (Calendar)	61GBC	25	1971	S
61	56A	Auto	61 Grand Seiko Special Weekdater	61GWL	25	1970	S	∅27.4; 5.6t	10
61	59A	Auto	Professional Diver 300 /61 Matic	6159	25	1967	S	∅27.4; 5.6t	10
61	59B	Auto	Professional Diver 600	6159	25	1975	S	∅27.4; 5.6t	10
61	85A,B	Auto	Grand Seiko V.F.A. (specially Adjusted)	6185	25	1969	S	∅27.4; 5.6t	10
61	86A	Auto	Grand Seiko V.F.A. Weekdater (specially Adjusted)	6186	25	1972	S
62	00	Hand	Seiko Liner	LN	23 (21)	1960	S	∅26.0; 3.3t	5
62	01B	Auto	Seikomatic/Matic Silverwave	MA	20	1960	S	∅28.0; 4.7t	5
62	05B	Auto	Matic Selfdater	MAS	17 - 24	1962	S	∅28.0; 5.3t	5
62	06A,B	Auto	Seiko Business/Matic Weekdater	62B-MAW	26	1963	S	∅28.0; 5.6t	5
62	15A	Auto	Seiko Professional Diver 300	6215	35	1967	S
62	16A	Auto	Matic Weekdater	62MWK	39			∅28.0; 5.6t	5
62	17A	Auto	Seiko Matic Divers Watch	62MAS	17	1964	S	∅28.0; 5.3t	5
62	17A	Auto	Seiko Matic Worldtime	MASWT	17	1964	S
62	18A,B,C	Auto	Seikomatic Weekdater	MAWK	35	1964	S	∅28.0; 5.6t	5
62	20M	Hand	Skyliner	SLN	17	1961	S	∅24.1; 3.8t	5
62	20B,C	Hand	Skyliner	SLN	21			∅24.1; 3.8t	5
62	20D	Hand	Skyliner	SLN	17 - 21			∅24.1; 3.8t	5
62	22M	Hand	Skyliner Calendar	SLNC	17			∅24.1; 3.8t	5
62	22A,B	Hand	Skyliner Calendar	SLNC	21			∅24.1; 3.8t	5
62	22C	Hand	Skyliner Calendar	SLNC	17 - 21			∅24.1; 3.8t	5
62	40	Hand	Liner Chronometer		25	1963	S	∅26.0; 3.5t	5
62	45A	Auto	62 Grand Seiko/Seikomatic Chronometer	62GAC-H	35	1966	S	∅28.0; 5.6t	5.5
62	46A	Auto	62 Grand Seiko Weekdater/62Matic Weekdater Chronometer	62GAW-H	39	1966	S	∅28.0; 5.6t	5.5
63	06	Auto	5 Actus		21	1976	S	∅27.4; 5.2t	6
63	09	Auto	Export Models Only		17	1976	S	∅27.4; 5.2t	6
63	10	Hand	63 Railroad Watch		17	1976	S	∅27.4; 3.4t	6
63	47	Auto	Moonphase (Only for Export)		23	1986	S	∅27.4; 5.8t	6
66	A,B	Hand	Sportsmen 17	SMS	17	1960	S	∅24.1; 3.8t	5
66	01A	Auto	Sportsmatic	SMAC	17 - 19	1961	S	∅28.1; 5.4t	5
66	01B	Auto	Sportsmatic	SMAC	17 - 19			∅28.1; 5.4t	5
66	02B	Hand	Sportsmen 17 Calendar	SMSC	17		S	∅28.1; 5.4t	5
66	05	Auto	Sportsmatic Calendar		19	1962	S
66	06B	Auto	Sportsmatic 5	SMA5	21	1963	S	∅28.1; 6.4t	5
66	18A	Hand	Visually/Hearing Impaired		17	1966	S	∅24.1; 3.8t	5
66	19A	Auto	Sportsmatic 5	66SA5	21	1964	S	∅28.1; 6.4t	5
66	40A	Hand	Disney Time		7	1961	S	∅24.1; 3.8t	5
66	42A	Hand	66 Schooltime		7
66	59A	Hand	66 Schooltime Weekdater		7	1964	S	∅24.1; 4.8t	5
66	60A	Hand	Seiko 6660	6660	21			∅24.1; 3.8t	5
68	00	Hand	Thin Dress Watch	6800		1969	D	19.7 x 16.9; 1.9t	6
68	10	Hand	Seiko Dress Ultra Thin	6810		1973	D	∅20.0; 1.9t	6
6S	74	Auto	Credor Chronograph			1998	D
70	01A	Auto	Automatic		17
70	05A	Auto	Seiko Automatic Calendar	70AC	17
70	06A	Auto	Seiko Automatic Calendar		17 - 19 - 21	1973	S
70	15A	Auto	70 5 Sports Speedtimer/Time Sonar	70 SPS	21	1970	D	∅26.0; 5.3t	5
70	16A	Auto	Chronograph Automatic		17	1976	D
70	17A	Auto	70 5 Sports Speedtimer	70SP	21	1971	D
70	18A,B	Auto	70 Seiko Chronograph (Weekdater)	70CMW	23	1971	D
70	19A	Auto	70 5 Actus/Seiko Advan	70-5A/70AD	21	1969	D	∅27.4; 4.8t	6
70	39A	Auto	Seiko Advan	70ADL	21
760		Hand	Fairway	FW	21	1962	D	∅26.0; 3.7t	5
761		Hand	Fairway	FW	21
76	05A	Auto	Sportsmatic Calendar DX	76SCD	23			∅28.0; 5.7t	5
76	06A	Auto	Sportsmatic 5DX	SMA-5D	23	1964	D	∅28.0; 5.7t	5
76	19A	Auto	76 5DX	76-5D	25		D	∅28.0; 6.4t	5
76	22A,C,D	Hand	Campion/Campion860	CHC86	17	1963	D	∅28.0; 4.3t	5
76	25A,C,D,E	Auto	Sportsmatic Calendar 820	SAC82	17	1964	D	∅28.0; 5.7t	5
790		Auto	Sportsmatic Calendar	SMC	19	1962	S
810		Hand	Chronos Special	CL	23	1962	D	∅26.0; 4.0t	5
820		Auto	Sportsmatic Calendar 820	SAC82	17	1964	D
830		Auto	Seikomatic Slim	MAM	30
83	01	Auto	Seikomatic Slim	MAM	30	1963	S
83	05B	Auto	83 Seikomatic Calendar/Matic Slim Date	MAC/MAMD	30	1963	S	∅29.0; 4.5t	5
83	05C	Auto	Matic Slim Date (with hand wind)	83MC	39			∅29.0; 4.5t	5
83	06A	Auto	83 Seikomatic Weekdater/Seiko BusinessA	83MW/83BA	30	1965	S	∅29.0; 4.8t	5
83	25A	Auto	83 Seikomatic Calendar	83MC	39			∅29.0; 4.5t	5
83	46A	Auto	83 Seikomatic Weekdater/Seiko BusinessA	83MW/83BA	27		S	∅29.0; 4.8t	5
840		Auto	Seikomatic Slim Date	MAMD	30
850		Auto	Champion 850 (Alpinist)	CH85	17	1963	D	∅26.0; 3.7t	5
851		Auto	Champion	CH85	17	1963	D
860		Hand	Champion/Champion 860	CHC86	17
88	00	Hand	88 Stopwatch	88ST	7
90	11	Hand	90 Stopwatch	90ST	7			∅40.3; 6.1t	5
91	19A	Hand	Railroad Watch	91RW	15			∅41.3; 6.4t	5
956		Hand	Skyliner Calendar	SLNC	21
957		Hand	Sportsman 17 Calendar	SMSC	17
9S	51	Auto	Grand Seiko (Calendar SS Bracelet)		26	1998	D
9S	55	Auto	Grand Seiko (18k strap)		24	1998	D	∅28.4; 5.3t	8