Seiko's chronograph has a history spanning more than half a century. While numerous chronograph watches have been released to date, this article traces some of the most iconic models in chronological order, exploring the impact that Japan's chronographs have had on the world. The article is written by Gisbert L. Bruner, a world-renowned watch journalist and familiar contributor to Chronos Japan. Having spent time at the Seiko Museum researching the history of the chronograph, this renowned journalist provides a clear and concise account of the history of Seiko's chronographs.
Text by Gisbert Brunner
Edited by Yuzo Takeishi
Articles published in November 2020
Caliber 5719: Japan's first wristwatch chronograph
When Seiko began producing Japan's first chronograph wristwatch, its goal was to create a timepiece that would be a status symbol rather than a timekeeper. Seiko's Suwa Seikosha workshop in Suwa, Nagano Prefecture, developed the watch for the 1964 Tokyo Olympics. It featured the 12-ligne (27.6mm diameter) manual-winding caliber 5719. This 6.1mm-thick movement featured a single push-button for activating the chronograph, a horizontal clutch, and a column wheel for start/stop/zero reset. Its vibration frequency was 2.5 Hz, or 18,000 vibrations per hour, and it offered a power reserve of approximately 38 hours with the chronograph running. The case was made of stainless steel and measured 38.2mm in diameter and 11.2mm thick.
Because the watch lacked a counter, Seiko used a rotating bezel with minute markings. To measure times longer than one minute, the chronograph was started, then the tip of the triangular marker was aligned with the minute hand. Once the time measurement was complete, the chronograph was stopped and the elapsed minutes were read using the rotating bezel, while the elapsed seconds were read from the dial. One problem with the first chronograph series was that the plastic rotating bezel was prone to breaking, but Seiko later replaced it with a more durable stainless steel bezel, eliminating this issue.
Seiko also offered another version of the chronograph movement: the 6.4mm-thick caliber 5718, powering a limited edition stainless steel model. This is an extremely rare and highly sought-after model among collectors. What appears to be a date display at 12 o'clock on the dial is actually a "golf stroke" or "point counter," operated by two buttons on the left side of the case. The dial also featured a subdial at 6 o'clock that doubled as a 60-minute counter and small seconds, and a tachymeter scale around the outer edge of the dial. (Editor's note: The point counter at 12 o'clock advances one digit every 24 hours, so it can also be used as a date display.)
Caliber 6139: The world's first automatic chronograph
It's well known that Swiss watchmakers were competing to develop automatic chronographs in the 1960s, but few know that Japanese manufacturers also joined the fray. Seiko began development of the automatic calibers 6139 and 6138 in 1967. The caliber 6139, developed over just two years, was an astonishingly small movement, measuring just 27.4mm in diameter and 6.5mm thick. The mainspring, wound by a central rotor using ball bearings, was linked to a Magic Lever system still used today, transmitting energy via a bidirectional winding system. Furthermore, when fully wound and with the chronograph running, it offered a power reserve of approximately 36 hours.
To improve performance, the developers increased the vibration frequency from the then-standard 2.5 Hz (18,000 vph) to 3 Hz (21,600 vph). Other technical features include a column wheel to control the chronograph, a 30-minute counter at 6 o'clock, and a vertical clutch. The vertical clutch was a revolutionary transmission method for the time, adopted much earlier than Swiss watches. Seiko also offered a bilingual (Japanese and English) day of the week display in addition to a date display.
The 61 Five Sports Speedtimer, powered by this new movement, was released in mid-May 1969, meaning Seiko had won the race to market the world's first automatic chronograph (competitors Zenith and the four-way alliance of Breitling, Heuer, Büren, and Dubois-Dépraz released automatic chronographs later that year). Meanwhile, the 7.9mm-thick Caliber 6138 debuted in 1970. Unlike the Caliber 6139, it featured a small seconds and a 12-hour counter. The Caliber 6138 was incorporated into "Bullhead" models, which featured pushers on the top of the case, similar to Omega's Seamaster Bullhead.
Incidentally, Seiko was also the manufacturer that sent the first automatic chronograph into space: when American astronaut William Pogue orbited Earth on the Skylab 4 mission in 73-74, he was wearing a model equipped with the caliber 6139 (commonly known as the Pogue Seiko).
Caliber 7017: A slim automatic chronograph
In 1970, Daini Seikosha, now Seiko Instruments (SII), released a mechanical chronograph movement called the 1970s Series. At just 5.9mm thick and 27.4mm in diameter, the Caliber 7017 was the world's thinnest automatic chronograph at the time. While elements such as the Magic Lever, column wheel, and vertical clutch recall the Caliber 6139, the Caliber 7017 was an entirely new movement with special features. The reduced number of parts made the movement more compact and easier to maintain. While the goal of achieving the world's thinnest watch meant that a counter was not possible, the Caliber 7017 still featured a day-date display.
Caliber 7018, also thin and equipped with a 30-minute counter, was released in 1971. Caliber 7015 and, considered Seiko's pinnacle, Caliber 7016 were released the following year in 1972. The latter, in particular, featured a subdial with two hands at the 6 o'clock position: one for the small seconds and the other for the 30-minute counter.
Seiko (Dai-ni Seikosha) stopped manufacturing mechanical chronograph calibers in 77, and then completely stopped manufacturing mechanical watches in the early 80s.
The machines used in production were scheduled to be disposed of, but veteran employees rebelled, which led to a renaissance of mechanical watches in Japan in the mid-90s, following a few years earlier in Europe.
Caliber Series 6S: The Rebirth of the Chronograph
In 1988, Seiko (Seiko Electronics Industries, now Seiko Instruments) resumed production of mechanical chronographs with the help of veteran engineers and watchmakers. Some of these members were already retired, but they agreed to participate in the project. The 28.4mm Series 6S was initially planned to be installed in the Credor watch and sold only in the Japanese market. The 5.8mm-thick manual-winding Caliber 6S74, released in 1988, had a frequency of 4 Hz (28,800 vph) and a power reserve of approximately 60 hours. While it lacked a date display, it featured 30-minute and 12-hour counters and a power reserve indicator. Like previous models, the Caliber 6S74 used a column wheel. However, the transmission system was changed from a vertical clutch to a swing pinion. (Editor's note: Seiko Instruments has since exclusively manufactured Seiko mechanical movements.)
Seiko subsequently developed a series of chronograph movements from this base caliber. Among these was the 7.2mm-thick caliber 6S77, which debuted in 1999. It was an automatic movement with a Magic Lever mechanism, featuring a date display and a power reserve of approximately 50 hours. The automatic caliber 6S78 was also released in 99. The caliber 6S99, a skeletonized version of the 6S74, appeared in 2000, followed in 01 by the caliber 6S37, which featured both a date and power reserve indicator. The caliber 6S96, based on the caliber 6S77, had a 60-hour power reserve but no date display.
The last movement is the Caliber 6S28, which is based on the Caliber 6S78 introduced in 05. With this movement, Seiko implemented changes similar to those made by ETA to the Caliber 7750. That is, the 30-minute counter has been moved from 12 o'clock to 3 o'clock in the Caliber 7753. The date display in the Caliber 6S28 is located between 4 and 5 o'clock on the dial. (Editor's note: Calibers 6S74, 96, and 99 have a power reserve of approximately 60 hours. The other 6S models have a power reserve of approximately 50 hours. The weight of the pushers has also been changed between the early models and the others.)
Seiko supplied the caliber 6S78, known as the "TC 78," to other companies, including Junghans, which renamed the movement the J890. TAG Heuer also purchased the TC 78, but heavily modified it with in-house parts to become the caliber 1887.
Caliber Series 8R: Today's Seiko Chronographs
In 2009, 40 years after the birth of the world's first automatic chronograph, the caliber 6139, I visited Seiko's booth at Baselworld and saw the latest model of the automatic chronograph, called the "Ananta." (Editor's note: No longer in production.) It was powered by the caliber 8R28, a movement that entered mass production in 2008. This model combined traditional Seiko chronograph features—a column wheel, vertical clutch, and Magic Lever—with innovative mechanisms like an integrated trident hammer, which instantly resets all chronograph counters to zero. The 8R28 boasts a 45-hour power reserve and its balance, balance spring, and escapement are all manufactured in-house. The movement is 28mm in diameter and 7.2mm thick. It beats at 4Hz (28,800 vph) and is composed of 292 parts. (Editor's note: The 8R caliber differs from previous chronographs in that it features a dial-side chronograph mechanism.)
The following movement, the Caliber 8R39, released in 11, was designed for divers' watches and was 7.6mm thick. The Caliber 8R48, released in 14, was 7.5mm thick and was used in the "Brightz."
The Seiko movement that can replace the ETA 7753 is the NE88A chronograph movement, which Seiko currently sells. This movement was released in August 2014 based on the 8R39 and is 7.63mm thick.
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