One aspect of watch history that is both misunderstood and misrepresented is Seiko’s internal competition from the 1950s to the 1970s. It is vital to get a better understanding of this era because it is, arguably, the most important in Seiko’s history. This was the time that Seiko transformed from a struggling company in Japan to the world’s largest watchmaker. In researching this era, we have corrected a number of online urban legends, uncovered new information, and made educated guesses about the parts of the story that are still shrouded in mystery.
Myth One – The 1959 Factory Split
The most prevalent myth that exists is that Seiko “split” their company in 1959 to create and foster competition. While 1959 was the year of Suwa Seikosha’s official inception as an independent subsidiary, the truth of the factory split is more complicated and nuanced.

(From the collection of Steve Sundberg. oldtokyo.com)
To understand the factory split, we need to look back to the beginning of World War Two. At that time, Seiko as we now know it was two entities: K. Hattori and Company, a clock manufacturing and sales company with its famous Hattori Tokeiten store in Ginza and the original Seikosha factory, and a second factory, known as Daini Seikosha, a watch manufacturer.
All enterprises were located in Tokyo, and were owned by the Hattori family but they were controlled independently. As war loomed on the horizon, Daini Seikosha wanted to find evacuation sites outside of Tokyo. It also needed to increase manufacture.

In May 1942, Hisao Yamasaki, an ex-employee of Hattori Tokeiten – Kintaro Hattori’s original Tokyo clock shop – started his own watch company called “Daiwa Kogyo, Ltd.” in the Suwa area of Nagano. Soon after, in 1943, Daini Seikosha expanded production by partnering with Daiwa Kogyo, Ltd. forming a joint-venture known as “Daini Seikosha (Suwa).” The new venture operated a separate factory in Nagano under the control of the factory in Tokyo.
As feared, the Daini Seikosha factory in the Kameido part of Tokyo was destroyed before the end of the war and Seiko was forced to restart watch production using only its evacuation sites until the Daini factory could be rebuilt. In 1949 the evacuation sites at Kiryu, Toyama and Sendai were closed as watch production resumed at the rebuilt Kameido factory in Tokyo. At that time Mr. Yamazaki convinced the Hattori family to retain the factory in Nagano. Thus, the “Suwa” factory continued operating, but as a subsidiary of Daini Seikosha, not K Hattori & Co.

However, the quality of the watches produced after the war failed to meet Seiko’s earlier standards. A lack of raw materials, the stagnation of Japan’s industrial landscape and the upheaval of moving production from Tokyo to smaller evacuation sites and then back to Tokyo meant that Seiko was no longer producing quality timepieces. Seiko’s watches were not even able to compete well in domestic competitions let alone on the international stage.
At this time, Seiko were using either rebranded Moeris 10 movements in their wristwatches, or more likely, after the war, copies of these movements manufactured locally. Seiko called these movements their “caliber 10 movements” and they were used by both the Daini and Suwa factories in the late 1940s. The caliber 10 was further developed by the Suwa factory in 1946 into the 10A by using a separate bridge for the second and third wheels and separate cocks for the fourth and escape wheels.
The Daini factory made similar modifications to the Moeris base movement in 1948 to arrive at the 10B caliber by using a separate bridge for the second, third and fourth wheels. Presumably, the modifications still did not bring the necessary quality improvements because in 1950 the Suwa factory launched the ‘Super’ which appears to be very similar to the 10.5 ligne (23.7mm) ETA 1080 movement launched the same year.

The ETA 1080 was a ground breaking movement and defined the architecture of many manually wound movements for the next decade. The similarity between the Seiko movement and the ETA movement developed at the same time is remarkable. While the size and overall architecture are clearly the same, the actual location of the pinions do not line up exactly so one movement is not a direct clone of the other. However, the ‘Super’ was never claimed by Seiko to be an in-house movement so does this mean the super was in some way related to the Swiss movement? We think it probably was.
The ‘Super’ was Seiko’s first center-seconds movement. The Moeris-based designs up until then all used a sub-second layout. Both Suwa and Daini factories started using the ‘Super’ movement from 1950 onwards and dropped the Moeris-derived movements they had been using.
So during the early 50s, both factories still seem to be cloning or modifying Swiss movements rather than designing their own. Genzo Hattori, the son of founder Kintaro, recognized that the existing company structure of both factories was limiting their ability to innovate. In 1953 he decided to install different management groups for the Kameido and Nagano factories and have them perform their research and development independently. [Keep in mind that while Daini was independent of K. Hattori & Co. on paper, both companies were owned by the Hattori family.]
So it is 1953, rather than 1959, that really represents the turning point from factory collaboration to factory competition to aid innovation. In fact, by 1959, competition between the factories was already long-established. Genzo Hattori’s structural change quickly bore fruit with the Daini Seikosha (Suwa) team developing the ‘Marvel’ in 1956. The larger movement of the ‘Marvel’ was a step forward in accuracy and reliability compared to the ‘Super’ and is generally accepted as being a 100% in-house development even though it kept the general architecture of the ‘Super’ and ETA.

With the success of the Suwa factory’s separate R&D, one can only imagine that Daini’s employees were under considerable pressure to match this innovation and produce their own movement. We believe that either management or the Hattori family themselves requested that the Daini factory produce a watch as good as, or superior to, the ‘Marvel’.
As mentioned, at this time the Daini factory was still using the Seikosha branded version of the ETA 1080 in their ‘Unique’ model. Their response came in 1958, two years after Suwa’s ‘Marvel’, with the caliber 54A that debuted in the Seiko ‘Cronos’. However, unlike Suwa that fully embraced their in-house movement, Daini were still using the ETA-like ‘Super’ movements in the ‘Unique’ as late as 1960!

And so as the 1950s drew to a close, a movement arms race of sorts had began that would continue for much of the next decade. Each factory tried to one-up the other during this time, releasing new model derivations almost monthly in an attempt to show that they were the most innovative and competitive.
Myth Two – The Neuchâtel Trials
During the 1960s, both Daini and Suwa entered the Neuchâtel observatory trials in Switzerland and this is where another common myth exists. First of all, the trials are commonly portrayed as being entered by each factory separately: Daini vs Suwa vs the Swiss. While researching the Seiko episode for the Teamistry podcast, we heard first-hand from Hirokazu Imai, a representative of Seiko Epson (the modern descendant of the Suwa factory), that while the movements were entered separately, the factories combined resources in terms of sharing the best examples of components from both and in terms of the staff performing the regulation.

Secondly, it is often pointed out that Daini and Suwa performed poorly in the first few years that they entered the competition. This is most likely not due to poor movements, however, but to shipping the movements from Japan to Switzerland. After the initial failures in 1964, in which Daini and Suwa movements performed much worse than on home ground, engineers at the factories realized the movements were being magnetized and otherwise negatively affected during flight. They spent the next few years experimenting with different anti-magnetic alloys in their movements and flight cases and even different flight patterns to minimize this effect.
Thirdly, there is also misinformation regarding the 1968 trials in particular. That year, it was likely that Seiko’s movements would have finally, after almost a decade of failure, beaten the Swiss at Neuchâtel in the watch category. It is common knowledge that the competition was suspended shortly after the 45 days of testing started and a conspiracy theory developed that this was because the Swiss would not allow themselves to be beaten on their own turf.

However, the truth does not involve a conspiracy to save Swiss face, but rather quartz technology. By the late 1960s, quartz movements were being submitted in the watch category by Swiss manufacturers and they were inherently far more accurate than mechanical movements. The Neuchâtel group realized it wasn’t a fair fight and suspended the competition. Until 1968, quartz movements had only been entered in the marine chronometer class. As an aside, Seiko had entered a quartz movement in that class in 1964 and come 5th, but afterwards focused solely on mechanical watches at Neuchâtel.

After the suspension, Seiko instead submitted their mechanical movements to trials in Geneva. Those trials proved that Seiko, in fact, did have the best mechanical movements, with Daini’s outperforming all other mechanical movements. However, they lost out to prototype quartz watch movements – exactly the outcome Neuchâtel had succeeded in avoiding.
Myth Three – The Role of Taro Tanaka
Another common misunderstanding about this time revolves around the role Taro Tanaka played in the company. Mr. Tanaka is best known for developing the “Grammar of Design”, a series of guidelines for designing watch cases and dials. However, how does one explain all the watches produced in the 60s and 70s that don’t follow his dictums, including some of Seiko’s most prestigious watches, such as the very limited 1968 edition 45 GSN Daini Neuchâtel Chronometer?
The variance is partially because Mr. Tanaka did not design all the watches directly. He was an employee of K. Hattori, not Daini or Suwa. Head office would provide design guidelines and – if Mr. Tanaka wasn’t designing the watches himself – would give final approval. It is clear that Daini followed the Grammar of Design early on, with Mr. Tanaka most likely playing a large role in designing the King Seiko 44-9990, a case design that flowed directly into the Grand Seiko line via Daini. He was also responsible for designing the first Seiko diver in 1965, the “62Mas” as well as a number of other divers and sport watches with Suwa. However, it seems that his influence grew at both factories from 1967 onwards after he started an internal Seiko design council, finally bringing together the design teams of K. Hattori, Daini and Suwa.

Another reason for the differing levels of Mr. Tanaka’s influence on each factory’s models was the markets they served. Suwa’s watches were predominantly for export overseas while Daini’s were local sales. We can assume that K. Hattori, understanding that Mr. Tanaka’s approach was based in Japanese philosophy and design, might appeal most to the local market. Conversely, they may have felt a more conservative approach to design would be more appealing in the US and Europe.
Myth Four – It was a Competition
Despite how intense the rivalry between Daini and Suwa was during this period, the Hattoris wanted to make sure it never became bitter or negative. Mr. Imai of Seiko Epson states that the relationship was framed as being a family, with the Hattoris as the parents, K. Hattori & Co. the first son, Daini the second son and Suwa the third son. So while it was natural for brothers to compete against each other for their parent’s favour, Mr. Imai says, they were fundamentally family, so they had to have mutual respect, understanding and support. This is the first time this relationship has been framed like this in any English language media.

Mr. Imai also revealed a few examples of how that sibling relationship played out, specifically in technology and information sharing. Until now, it has been difficult to find examples of the two factories sharing technology although Mr. Imai mentions two that are hidden in plain sight: Diashock and the magic lever. Both were developed by Suwa but immediately shared with Daini. Mr. Imai also revealed that during the Neuchâtel trials, all movements contained Daini mainsprings, including movements submitted by Suwa. It was understood that their mainspring development was superior, so both “brothers” shared this advancement.
Myth Five – The Grand Seiko/King Seiko Rivalry
It has also long been conjectured as to why, exactly, Grand Seiko was positioned as a luxury watch above King Seiko. Was it purely marketing or because the Grand Seiko concept was developed first? There is some evidence to be found in a 2004 interview with Taro Tanaka in Japan’s “Horological International Correspondence.” In it, he states that product manager Ren Tanaka (ten years Taro Tanaka’s senior and his mentor at Seiko, but no relation) received a proposal from Suwa Seikosha for a high-precision movement “with the goal of being a Swiss chronometer.” When planning for its marketing, Ren Tanaka came up with the name “Grand Seiko” because he envisioned it as the watch that would “catch up and overtake Switzerland,” or in his mind, a “great Seiko.”

After the release of the Grand Seiko, K. Hattori received a proposal from Daini Seikosha for their own high-precision movement “also built with the goal of being a chronometer.” Ren Tanaka’s first concept to name this watch was “Champion Seiko.” But as he further refined his thinking, categorizing Grand Seiko as “the highest peak of Seiko,” he decided that this second watch, while not at the same level, would be the “King of Seiko.”

Beyond Ren Tanaka’s approach to marketing the watches, we also dug deeper into the technical differences between the creation of Grand and King Seikos. Specifically, in 1960, Suwa developed their own internal movement testing system, in an attempt to be as rigorous as the Swiss. The Grand Seiko movements passed this test, which required far more time, skill and expertise. Daini, without such a testing system, did not have the same quality standards to apply to their King Seiko line. So while King Seiko was their pinnacle watch at the time, it was not made to the same high standards at the Grand Seiko. However, this was most likely also by design, to keep the price of the King Seiko lower than the Grand, to offer more variety to the consumer.
Despite the difference between Grand and King Seikos, it is also true that by the late 60s, both factories were producing versions of both watches. This is because of a “brand sharing” strategy introduced by the Hattori family in the mid-60s. Management realized that flooding the market with so many variations of Seiko models was actually starting to hurt the company. And so K. Hattori took over brand development, assigning specific watches to Daini and Suwa.
Initially Daini were asked to produce Grand Seiko because of one particularly accurate King Seiko model. The manually-wound 44KS was powered by the 4402 movement, which was fittingly a development of Daini’s original caliber 54 created many years earlier as an answer to Suwa’s own ‘Marvel’. The Daini 4402 movement was so good that Daini were asked to use it to create a Grand Seiko, the 44GS, now appreciated as one of the all time great vintage Seikos.
Despite the brand sharing, each factory continued to make GS and KS watches built around their own movements. However, there is also evidence that on a limited scale, some movements were also made in both factories. A number of 6139 movements can be found with Daini components for example, presumably to meet company-wide production targets.
Perhaps the ultimate evidence of collaboration however is the image of the movement below reproduced from wristsushi. The movement is a Suwa-designed hi-beat 5740C normally found exclusively in the Suwa-manufactured Lord Marvel. Yet here we find a 5740C clearly manufactured by Daini Seikosha to a slightly different design and even adjusted to a higher degree than the regular (unadjusted) Suwa 5740C movement.

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Note: This article was updated on Feb 10, 2021 on account of additional information received on the exact role of Taro Tanaka within the K. Hattori organization.