Seiko Movement Numbers History

Published: 2016-12-09 - By: gdm
Last updated on: 2018-12-15
visibility: Public
The Seiko Marvel from 1956


In the early to mid 60s, Seiko seems to have standardized its movement numbers, with the pattern xx06. The 3rd digit represents the grade of movement (so a 6246 is higher than a 6206) and the 4th digit represents the type of date display: 1 = no date, 5 = date only, 6 = DD).

But how consistent were they? Does this pattern apply to the 62x, 66x, 83x, and 57x series? There is likely some relationship among 6206 and other 62xx, but to what extent? For example, the 6201, 6220, and probably the 6222 seem to predate the 6206, so how can the 6206 be the base model for the 62XX series? A similar case can be made for the 66xx's, the Sportsmatics. The 6606 and 6619 appear to be related (they are similar movements), but the other 66xx movements seem less connected. The 6601-05 predates the 06. The 6606 and 6619 are date-only models, while the 6601-05 watches are not date-only. There are also some 66xx oddballs like the 6640 "Disney", or the 6642 and 6659 Schooltime, or the 6660, which is a 21j.

It is particularly interesting how the different movements are related to each other and which ones were evolved from which. Others appear to be entirely new designs. The following is a summary of research completed by different Seiko watch fans pertinent to post-WW2 men's watches.


First of all, as noted earlier, Seiko changed its movement numbering system in the early 1960s. The transition seems to have occurred around 1962-63. Many of the pre-1960s (3-digit) movements remained in service but were simply given new movement numbers with 4-digits. This article intentionally avoids discussion of movements which had been retired prior to the 4-digit transition including: Crown, Cronos, and Fairway.

With the introduction of the 4-digit series numbers, an important distinction can be made. The 76xx series that appeared at this time were part of the Daini line, while the 66xx and 62xx were Suwa products. The first digit of the movement fairly consistently will indicate which line this is part of.

Seiko 6206 Movement

The following is a list of the different series that were part of this numbering transition:
  • 2451: (Sportsmatic, 1961, Suwa), previously known as the 245 movement
  • 3140: (Liner, Suwa, 1960), previously known as the 620 movement
  • 4361. (Sportsman, Suwa, 1960 - previously cal. 66), previously known as the 436 movement
  • 5700. (Crown, Suwa, 1959), previously known as the 560 and 57A movements
  • 5722: (GS, Suwa, 1963), previously known as the 430 movement
  • 6200: Is closely related to the 603 movements though there are differences in the jewel counts
  • 6201: Like the 6200, it is related to the 603 but has a autowind function.
  • 6205: (Seikomatic Selfdater, 24j, 1962, Suwa), previously known as the 394 movement
  • 6206: (Weekdater, Suwa), uses a modified version of the 400 movement
  • 6220. (Skyliner, Suwa, 1961), previously known as the 402 movement
  • 6222A/B (Skyliner Calendar, 21j, Suwa), previously known as the 956 movement
  • 6602 (Sportsman Cal, 17j, Suwa), previously known as the 957 movement
  • 6606: (Sportsmatic 5, Suwa, 1963, first 5 date), previously known as the 410 movement
  • 6240. (Liner Chronometer, Suwa, 1963), previously known as the 460 movement
  • 7622 (Champion, 17j, Daini) , previously known as the 860 movement
  • 7625 (Sportsmatic Cal, 17j, Daini) , previously known as the 820 movement
  • 8305, 8305B (Seikomatic Slimdate, 30j, 1963, Suwa), previously known as the 840 movement
  • 8325A. (Seikomatic Calendar, 39j, 1965?, Suwa), previously known as the 395 movement, Note - the 395 has no fine adjuster
  • 8301 (Seikomatic Slim, 30j, non-calendar, Suwa) , previously known as the 830 movement

Early Beginnings

Seiko had two watch factories after the war, Suwa and Daini-Kameido-Tokyo (or simply Daini). Both plants were part of the Daini portion of the Seiko organization - only later were these referred to as Suwa and Daini.

In the time period immediately following World War II, Seiko's primary watch, and their first with a true sweep second hand, was the Super. This was a Suwa product, which was introduced sometime around 1950 (A Journey in Time lists it as 1940, but this is likely an error). The Super also had a calendar version, the AutoDator, with a fourth center-mounted hand and dates around an inner ring. At the same time, Daini came out with a similar but thinner design, the 'Unique'. It is unclear whether either of these two models had movement numbers and they don't appear in the standard movement lists. Seiko made numerous gradual refinements as they attempted to come up to Swiss standards. It is likely there were so many versions of these two movements that it would be silly to try to track them by some kind of numbering system.

Early Refinement

Seiko's next major design leap came out of the Suwa factor. This was the 'Marvel' model which was introduced in 1956. The major innovation of this product was the addition of an auto-wind capability. Seiko called this capability the 'Gyro Marvel' and gave it a movement number! This model was known as movement 290 and it was produced from 1956-59 by Suwa. It was finished with 17, 19 or 21 jewels - at different price points.

The Daini design team soon followed with the 'Cronos' model in 1958 - and named the movement '54A caliber' This movement was thinner (a Daini theme) and had a bridge anchored at both ends, using the Diashock technique.

Suwa quickly responded in 1959 with the 'Crown' model using a new movement, the '560 caliber'. From this base model, Suwa also developed the 3180 Grand Seiko in 1960. The 5720 Grand Seiko also came out in 1960 with 25 jewels, followed by the 5722 calendar at 35 jewels in 1963. All these movements were hand-wind-only.

Both factories were very busy improving their movements and competing with each other as well as other brands. The Crown and Cronos went through several versions. In 1961 Suwa introduced the 57A and B versions of the Crown as well as the 5760 Special and the 341 Special. Each of these releases was an incremental improvement of the Crown design and were created with different levels of finish with different price points. This allowed customers to select from a range of different qualities and feature sets. Simultaneously, Daini developed and released the 810 Cronos Special in 1962.

Also during this time, Seiko first started targeting the more affluent consumer by developing a new 2nd-tier high-end watch category. The new 'King Seiko' would be one notch below the Grand Seiko. Unlike the Grand Seiko, which had versions from both Suwa and Daini, the King Seiko seems to have been purely a Daini product for its entire existence (44, 44xx, 45xx, 56xx, 52xx), except for the 56xx's. The King Seiko started with a mystery caliber in 1961, It was a 25 jewel non-hacking movement. There seems to be some controversy in the archives about whether this mystery caliber is an early version of the 44A, or whether a wholly different movement. The latter seems more likely given the fact that the first King Seiko was non-hacking, and the 44A was not introduced until 1964. Therefore it is likely the King Seiko was always had hacking capability.

In parallel with the ongoing development of the Cronos and the advent of the King Seiko, Daini came out with a short-lived high-end, slim watch called the Goldfeather, caliber 60A. This watch was released in 1960, and came in both 17 and 25 jewel versions. The Goldfeather was not popular and died out quickly.

Suwa's next mainline product was the 'Liner', which was introduced in 1960 and also went through several iterations. In 1960 Suwa released movement 3140 (also known as movement 620). This was am evolutionary step in thin dress movements. The 3140 was the basis for the later 62XX Seikomatic series. In 1963 they followed up with the 'Liner Chronometer' with movement 6240 (also known as the 460). None of these watches had a hacking capability. Among those that were automatics, none were capable of hand-winding.

The first Seikomatic was the 6201--the next automatic after the Gyro Marvel. The 6201 is basically the 'Liner' with auto-winding added on, similar to the way the Gyro Marvel evolved from the Marvel. In 1961 the 6601 Sportsmatic was another automatic. Other existing 3-digit movements seem to have been incorporated into the 62x Seikomatic line.

The Sportsman also came out of Suwa in 1960: movements 175, 436/4361, and 66, then the 957/6602 calendar (year unknown). This may have been the predecessor to the Sportsmatics, and indeed the 957 became the 6602, and the 66XX series was the Sportsmatic series.

An Era of Rapid Innovation and the Ascendancy of Suwa

Suwa introduced the 402/6220 'Skyliner' was introduced in 1961. They followed up with the 956/6222 'Skyliner Calendar' (non quickset date), apparently in the same year. The Skyliner moved on to the 61A and 6102 in the late 60s, which were the movements used for the edgier-styled Skyline models.

The 6201 Seikomatic and 6220 Skyliner in 1960 and 1961 seem to be the genesis of the 62xx series. This series has so many notable movements. 1962 seems to be the beginning of a rapid acceleration in the number of different movements and models. There has been debate about whether the 35j 6218 was a dry run for the 6245 GS (same jewel count, different fine adjuster type, and different calendar, with the 6218 being D/D and the 6245 date only). It seems more likely that the 39j 6216 was a dry run for the 6246 GS. The 6218, in turn, seems to be an improved version of the 6206, which itself is a revision of the 400. [Source:]

The 6201 series underwent a series of evolutionary steps in the early 1960s. In 1960, Seiko introduced the 6201 Seikomatic (previously known as the 603 movement). In 1961, they introduced the 6220 Seikomatic (previously known as the 402). In 1962, they released the 6205 Selfdater (previously 394). In 1963 they came out with the 6206 Weekdater (previously 400) and 6240 Liner (previously 460). In 1964 came the 6218 'Seikomatic' and 6217 'Silverwave'. In 1966 we saw the 6245 and 6246 Grand Seiko. In 1967 they introduced the 6215 300m diver. We also saw the 6222 (previously 957) 'Skyliner Calendar' and 6216 39 jewel (previously 395). Whew!

Seiko 6246 Movement

62XX Notes: Many, if not all, of the 62xx movements were hacking, but none were handwind-capable and among those with a day of week, none offered quickset on the day of the week. The 6222 Skyliner was not even quickset date. The 6216 and 6218 had both the dolphin and crown logos on the back. The 6216, 6245, and 6246 movements have rack & pinion fine adjuster, while the 6218 has the tadpole.

In parallel with the 62xx series, Suwa also developed the 66xx series, which boasted the 'Sportsmatics' and were the first watches to be marketed as 'Seiko-5's. The 66XX movements are slightly thicker than the 62XX'ss. The 66XXs were also not hacking, handwind-capable, or quickset.

In 1963, Suwa developed the 83XX series. This new series was similar in many respects to the 62XX series but with a focus on thinner movements. Some of these may have been reworkings of the 62XX's. The reworked versions were known as 'Seikomatic-R' with the 'R' presumably meaning reworked. The 83XX line was comprised of the 8305 (was either the 830 or 840), 30 Jewel Slimdate, the 8306 30 jewel Business/Weekdater (often bearing a Sealion logo), the 39 jewel 8325, and the 27jewel 8346.

Throughout the late 1950s and early 1960s, the Daini plant seemed to be able to produce equivalent-quality products to those of their sister plant, Suwa. However, the 76XX series, developed in 1963-64 was arguably a lower quality product group. This line included the 'Champion' and the predecessors to the DX models. Then, nothing new came out of Daini until the 1967 51XX series. They then went quiet again until the early 1970s, when Daini released the 70XX series. The 70XX movements were known for being chronographs with a flyback complication that was similar to the Suwa 6138/39 chronographs. This is probably because Daini had chief responsibility for ladies movements, and indeed there is a plethora of 2xxx ladies movements in the 60s.

The 'Champion' was a mid-grade movement when compared to Suwa's high-end 'Cronos'. Throughout 1963, Suwa evolved this movement through the 850, 851, and 7622 (860) versions. One of these models was known as the 'Flying Fish'. Daini also produced a 'Fairway 760/61' in 1962 with both 17 and 21 jewel movements. They later followed up with the 820/7625 Sportsmatic Calendar in 1964, which was the final model in the 76XX series.

Also in the early 1960s, Suwa developed the 57XX series. These models were produced at the same time as the 62XX and 66XX lines. The 57XX is a bit of a hodgepodge. The line included the 5720 Grand Seiko from 1960, the 5760 Crown Special from 1961, the 5722 Grand Seiko from 1963, 571X hand-wind chronographs from 1964, and the 5740 'Lord Marvel', which came in lo-beat (18k, 5740A/B, 1964) and hi-beat (36k, 5740C, 1967) versions. Internally there may be some relation between all these different 57XX movements, but it is not readily apparent.

The final series from the 1960s is Seiko's 44XX movements. These are high-end hand-wound movements. They are descended from the earlier King Seiko model. They were mostly produced from 1964 to 65 at the Daini plant.

The Product Lines Mature, and the Continued Dominance of Suwa

The Seikomatic and Sportsmatic lines were retired in 1967. They were replaced by the thinner workhorse 61XX movements, which were used in everything from the 6102 'Skyliner' and 6106 dress watches, the 6117 'Navigator' and 'World Timer' watches, to the 6105 'Diver', to the 6138/39 chronographs, as well as the 6145 and 6156 Grand Seiko. They were also used in the 6185/86 Grand Seiko VFAs, and the 6159 300m and 600m divers. Suwa produced three different 'tiers' of Grand Seiko: the "standard" Grand Seiko (2A) in calibers 6145 & 6146, the 'Special' (3A standard) in calibers 6155 & 6156, and the 'VFA' (4A) in calibers 6185 & 6186. The 3rd digit of the caliber number was used to designate the accuracy standard which the movement conformed to. The 4th digit determined the type of display (5 = date; 6 = day/date). According to the tech manuals, most or all of these are derived from the 6106 as the base movement. At the same time, Suwa developed the 4005/06 Bellmatic.

In fact, at around this point, Seiko seemed to have made the first serious effort to standardize their movement numbers. Her we see the first two numbers as the 'base'. The 3rd digit signifies the grade of movement (so a 6246 is higher than a 6206). The 4th digit indicates the date display type: 1 = no date, 5 = date only, 6 = day and date).

During this time period, Daini developed the 51XX series, which includes the 5106 (1967) and 5146 Presmatic (1969), but also some Seiko 5 DX movements, the 23 jewel 5126 and the 27 jewel 5139. There is also the 5106 'Weekdater' and the 5105 and 5125.

Seiko 5106 Movement

In 1968, Suwa developed the 56XX high-end movement for the King and Grand Seiko lines. The King Seiko saw the addition of the 'Vanac' and the 'Lordmatic'. The Grand Seiko saw the introduction of the 5641, 5645, and 5646 watches in 1970. Daini followed up with the competitive 52XX series starting in 1969. The new Daini movement immediately became the new standard for the King Seikos for both the 'Vanac', and 'Lordmatic' watches. Both the 56XX and 52XX movement series had hacking, auto-winding and quickset features. The Daini 52XX later became the 4SXX series. The Suwa Lordmatic (56XX) is manufactured to the Seiko "C" accuracy standard while the Daini Lordmatic Special (52XX) is "B" standard and runs at a 28,800 b.p.h. beat rate (Suwa Lordmatic is not "high beat" - probably only 21,600 b.p.h.).

In parallel with the 52XX series, Daini also developed the high-end handwind 45XX King Seiko/Grand Seiko series. The VFA version of the 45XX took 2nd place in the Swiss Neuchatel chronometer competition. It is possible that the engineers at Daini were given responsibility for developing movements for the Swiss competitions. This would explain their lower productivity in terms of new movements, as well as the various VFAs from Daini.

It is important to note that the Daini 45GS "VFA" models 4520A & 4582A that were entered into the Swiss observatory contests were not "production" VFAs, but specially constructed models with accuracy & performance standards that differed from the "4A" (men's GS VFA) standard. Quite clearly the Grand Seiko VFA had a "Daily Rate" of -2 to +2 seconds while the Astronomical Observatory Chronometer used was only -8 to +8.

The Advan line, which appeared about this time, were "mid grade" modernistic style watches produced with 6106, 7019, & 7039 movements (thus being made by both Suwa and Daini divisions). There could be though of as 'mid quality Vanacs'.

The Ascent of Quartz

The 6306, 6309, and 700x in the 1970s seem to have been the last mainstream mechanical movements. 630X were Suwa. 70XX were all Daini. The TZ movement table must have an error here: it lists the 7006 as Suwa, even though it was the base movement for the 701X movement.

Seiko Astron Movement

At this point, Seiko was shifting heavily to quartz, and except for the divers, it seems they stopped making mechanical watches entirely until the 1990s. They certainly had a number of firsts in the meantime, with the first quartz on the market, the first quartz chronograph, and I think the first watch with an IC (was this the 6M series)? Later came the Kinetic (autowind mechanism to charge a capacitor to drive the quartz movement) and most recently the Springdrive (mechanical, with a quartz oscillator to check the rate--charged via a Kinetic-like mechanism).


The original version of this article was written for the Seiko Citizen forum in August of 2006 by 'Kwahoo'. Thanks to Christopher Huang for helping me locate the original. Kwahoo stopped posting on that forum in 2009. Kwahoo listed a series of sources for his work, but sadly almost all of those links are now dead. The one remaining one is listed below, but it is in Japanese.

This article was modified from the original text to present the information in more of a textbook form with much of the conjecture and 'head-scratchy' text removed. It does refer to "A Journey in Time" which is a freely distributed text (written by Seiko Corporation staff) which we host a copy of locally. I hope Kwahoo is doing well and appreciates this homage to his efforts.