Chronography 10: Three Excellent Vintage Calibers from Seiko and Citizen

In 1969, Seiko’s 6139 chronograph caliber was nothing short of revolutionary, incorporating a column wheel and a vertical clutch system. Seiko certainly didn’t invent the vertical clutch (historians believe that honor belongs to Pierce), but it was certainly the first to bring this technical achievement back to the forefront of chronograph technology. Many other watch companies have since followed suit and have incorporated the vertical clutch system into their chronographs.

In 1970, Seiko Daini (read our history explaining the Suwa/Daini split here) came out with the 701X family of chronographs, which were for a time the thinnest vertical clutch chronographs in the world until F. Piguet released the 1185 chronograph in 1987.

And then there’s Citizen, Japan’s other horological powerhouse. Citizen was not resting on its laurels, and in 1972 the firm released a range of automatic chronographs within the 81X0 family. Not being the first to market, Citizen had three years to improve on what had come before. The 81X0 is often overshadowed by Seiko’s offerings, but I believe that it is the more technically advanced of the group.

In the first part of our series looking at Japanese chronograph movements, we’re going to do a basic overview of these three great movement families.


Seiko 613X

I’ll begin with the 613x family from Seiko Suwa. There are two primary calibers: the earlier 6139 introduced in 1969 (and produced until approximately 1977), and the 6138 introduced a year later in 1970. The difference between the two movements is that the 6139 only has a 30-minute chronograph register, and the 6138 has an additional 12-hour register. Both lack an active running seconds and in terms of specs, they beat at 21,600bph and have a power reserve of 45 hours. Both also have a day/date indicator. The 6139 has 17 jewels, and the 6139 has 21 (and 23 for some of the rarer Japanese domestic market variants like the 6138-8000). Both variants lack hacking and the 6139 does not hand wind. In terms of size, the 613X is 27mm in diameter and 7.2mm (6139)/7.9mm (6138) tall.

Seiko 6138 8020 “Panda.”

The 613X family has numerous claims to fame, particularly the 6139. Alongside Zenith and the Chronomatic partnership, Seiko is widely acknowledged to be among the first companies (and some might even argue that Seiko was the first) to have an automatic chronograph watch out on the market. Peculiarly, this achievement was never marketed by Seiko nor given any mention in the official Seiko history, “A Journey in Time: The Remarkable Story of Seiko.” One fact that cannot be argued, however, was the Seiko was certainly the first Japanese watch company to produce and release an automatic chronograph.

Incidentally, the 6139 is also the first automatic chronograph sent to outer space, worn on the wrist of US astronaut Willian Reid Pogue during the 1973 Skylab-4 mission. This particular iridescent yellow-dialed model has now been nicknamed the “Pogue.”

Seiko 6139 6002 “Pogue.”

The combination of a column wheel and vertical clutch system pioneered by Seiko eventually saw widespread adoption by many Swiss companies–e.g. Rolex’s 4130 Daytona movement introduced in 2000, some 31 years later—a tacit acknowledgement of the superiority of this system. However, several haute horology brands are still using the traditional column wheel and oscillating pinion or horizontal coupling system because of the additional space that it allows them to finish their movements.SEIKO_6139_MOVEMENTThese days most people would associate vintage Seiko chronographs with this particular Seiko movement family.

Seiko 701X

The 701X series is arguably the more technically advanced of the two vintage Seiko chronograph movement families. It has an additional flyback functionality (which allows the user to immediately restart the chronograph without having to first stop and reset) and some models featuring a unique stacked hour and minute chronograph register. This means that there is one sub-dial for both the hour and minute hands counting off the elapsed time, versus the individual hour and minute sub-dials of its 6138 cousin. This makes reading the elapsed time harder, but it leaves the dial with a compact and clean design, one that was totally ingenious at the time.

7016 stacked sub-dial; photo credit

There are several notable variants within the 701x family. The most famous is the 7016 with the aforementioned stacked sub-dial. The 7015 and 7017 both feature only a central chronograph hand with no additional registers for recording elapsed time. Finally, the 7018 was much like the Suwa 6139 with only a 30-minute register.

Seiko 7015 “Time Sonar”; photo credit via pbase.

As mentioned earlier, this was also the thinnest vertical clutch column wheel chronograph for a period of time, existing from 1970 through ’77. Like its Suwa counterpart, the 701x beats at 21,600bph, has a central chronograph hand and lacks an active seconds hand. It also has 17 jewels and a day/date complication. The power reserve is approximately 42 hours and it cannot be hand wound or hacked. The movement has a diameter of approximately 27mm and is only an astounding 6.4mm tall, which is significantly thinner than the 6139.

Citizen 81X0

Finally, there’s the Citizen 81X0 family. Introduced in 1977 and running through 1980, the 81X0 consists of two calibers: the 8100 and the 8110. The former features a 30-minute chronograph register and the latter has an additional 12-hour register.

Citizen Challenge Timer “Bullhead” with 8110 movement.

As mentioned, Citizen had the advantage of being able to build on what Seiko had already released. With that, the 81X0 family comes in at a higher beat rate of 28,800bph and incorporates a flyback function. Moreover, the movement can be hand wound and comes with the column wheel vertical clutch system introduced three years earlier by Seiko. Further specs include 23 jewels and a 40-hour power reserve.

The 8110 is 27mm wide and 6.90mm tall. The height lies in between its two Seiko rivals, the Daini 7016 and Suwa 6138. The 8100, lacking an hour counter, comes in at an astonishingly thin 5.82mm.

Citizen 8110; photo credit via Axel66, watchuseek.

Coupling the unbeatable combination of a vertical clutch and column wheel system with flyback functionality, the Citizen 81X0 chronograph family features the best of the two vintage Seiko chronograph calibers, and it even manages to exceed them by throwing in the higher beat-rate and hand winding capability.

Note that in the 1970s, 28,800bph was forward thinking, and even Seiko classified their 28,800bph King Seikos and Grand Seikos as high-beat. It was only recently that it became the de facto standard beat rate of mechanical movements. Heck, even the flyback functionality present in the Citizen is not common today in most modern chronographs, and be prepared to pay a lot more for it if you do want the complication.

To conclude, the Citizen 81X0 chronograph–given its stable of technically superior features and reasonable asking price–is probably the best vintage Japanese chronograph (and it ranks highly even among the vintage Swiss movements). In the next installment of Chronography, we will take a closer look at a Citizen “Challenge Timer” that houses this very capable movement.

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ZQ’s a die-hard Seiko lover, an obsession first sparked by the purchase of a Seiko Orange Monster, the original 7S classic. ZQ has yet to find his way out of the Seiko rabbit hole, dabbling in both vintage and modern, but his love extends to watches of all kinds. This isn’t ZQ’s first foray into the writing about watches, and he’s excited to bring his bank of knowledge to worn&wound. ZQ currently resides in Singapore with his family.