Collector's Guide: Seiko 6138 Chronograph

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The 1970s were a golden age for mechanical chronographs. From the iconic motorsport chronographs produced by Heuer to the austere military chronographs produced by Hamilton , Precista , and CWC , the decade produced an incredible number of unique vintage pieces.

Chronographs from this era are defined by their intricate dials with colorful details, bold angular case shapes, and innovative mechanical movements. There's something about the original designs from the 1970s that appeals to many vintage collectors.

However, some of the coolest vintage chronographs currently on the pre-owned market come from Japan, especially Seiko . During the 1970s, Seiko released dozens of automatic chronograph models, most notably their 6138 (double sub-register) and 6139 (single sub-register) lines. From this group came several watches that have since become cult classics for collectors, with memorable nicknames like the "Pogue" , the "Bullhead" , and the "Kakume" .

For collectors just entering the vintage watch market, vintage Seiko chronographs are incredible value. Although prices have skyrocketed in recent years, many incredible vintage Seiko watches can still be purchased for under $500. I'd venture to say they're still inexpensive, considering the 6138 and 6139 watch lines represent a significant milestone in watchmaking: the world's first self-winding mechanical chronograph.

Today we'll focus on the 6138 series, the much-loved Japanese double sub-register chronograph that has amassed many admirers and fans around the world.

General Description Seiko 6138

Nickname	Reference	Motion	Size	Rarity
"UFO" / "Yachtsman"	6138-001X	6138	44mm x 15.5mm x 19mm	Common
"Tokai Zara"	6138-002X	6138	43mm x 15.5mm x 19mm	Queer
"Kakume"	6138-003X	6138	43mm x 14mm x 18mm	Common
"Bullhead"	6138-004X	6138	44mm x 16mm x 20mm	Common
"Jumbo"	6138-300X	6138	42mm x 15mm x 19mm	Common
"Calculator"	6138-700X	6138	44mm x 14mm x 19mm	Queer
"Panda"	6138-802X	6138	40mm x 13mm x 19mm	Common
"Baby Panda"	6138-800X	6138	40mm x 13mm x 19mm	Queer

The 6138 movement

The 21-jewel Seiko 6138A was first released in 1969 and was the first fully integrated two-register automatic chronograph with a column wheel and vertical clutch. An iteration of this movement, called the 6138B , was later released which had 23 jewels . Both movements are self-winding, automatic, and quick-wind day/date, a stunning technical achievement for the time and one which beat many high-profile Swiss counterparts (including Breitling, Heuer, and Zenith) to market.

Seiko was (and remains) one of the few distinguished watch companies in the world that produces its movements and parts in-house. From the proprietary alloys used to strengthen the mainsprings to the lubricating oils used to keep the parts moving freely, everything in this watch was produced by Seiko.

Not many companies can do this, even today, putting Seiko on par with Rolex for its technical manufacturing achievements. In fact, there's speculation that Rolex adapted the column/wheel design and vertical clutch mechanism from this movement for the Daytona , a watch released 30 years later.

Notes on buying used

The Seiko 6138 chronograph line was affordable at the time of its release, and as a result, it often wasn't treated with much care. This means that most vintage models were heavily used, and many have undergone some form of restoration or polishing.

The most important aspect when purchasing a used 6138 is to ensure that the movement has been recently serviced and is in working order. The cost of servicing a vintage 6138 movement will likely exceed the cost of the watch itself, so be careful when choosing a pre-owned model.

The second most important aspect when purchasing these pre-owned watches is to inspect the case and ensure that it hasn't been overpolished. A hallmark of the 6138 design was the intricate cases, with their combination of subtle finishes, curves, and sharp lines. It's very easy for a clumsy polishing job to completely destroy the subtle edges and facets that make these watches so attractive.

Finally, there are currently several replacement parts available for this model. The mineral crystal, for example, is very easy to obtain, so don't be discouraged by buying a used model with a scratched or damaged crystal. The tachymeter bezel is also relatively easy to obtain; just be aware that this part may be a reproduction, and any 6138 with a pristine bezel is more likely to have other aftermarket parts. "Frankenwatches" are common, and watches containing a mix of parts from several early models (the 6139 and 6138 had several interchangeable parts) aren't as valuable as watches containing all original parts. Buyer beware.

Seiko 6138-001X "UFO"

Size	Motion	Thickness	Characteristics	Water resistance
44mm x 19mm	Seiko 6138	15.5mm	Day, Date, Tachymeter	70m

SEIKO 6138 "UFO" | PHOTO CREDIT @TIMEFORME84

One of the earliest releases in the 6138 line has been affectionately coined the "UFO" by early Seiko fans, a tribute to its vaguely alien case shape and tendency to "float" on the wrist with its hidden lugs. Also referred to by Seiko as the "Yachtsman," this colorful chronograph is a favorite among collectors.

One of its main defining features is the use of a large and a small subdial, with various color schemes used for accents on the hands and dials (red, orange, and yellow).

The 6138-0010 is the Speedtimer version (Japan domestic market), while the 0011 and 0017 were produced for export. The differences between these two are strictly cosmetic; the 0011 has a red seconds hand, a lighter orange checkerboard pattern on the subdial, and no mention of water resistance on the dial, while the 0017 has a yellow seconds hand, darker checkering, and is marked with 70 meters of water resistance.

Seiko 6138-003X "Kakume"

Size	Motion	Thickness	Characteristics	Water resistance
43mm x 18mm	Seiko 6138	14mm	Day, Date, Tachymeter	70m

SEIKO "KAKUME" | PHOTO CREDIT @JEN.SEN71

The "Kakume" is a highly collectible model in the 6138 line, and is named for its two square subdials ( "Kakume" is Japanese for "Square Eyes" ). It can be found in two colors, a blue dial and a champagne dial (which is the rarer of the two options). There is also a JDM version branded "5 Sports Speed-Timer" , while exported versions were labeled "Chronograph Automatic" . The champagne dial has a radial satin-brushed finish with an orange outer ruler and black subdials, while the blue version has white subdials and a blue outer ruler. Both variants have solid orange hands on the main dial and subdials.

It has a large 43mm case, with short, narrow lugs (just 18mm), which may look a little odd compared to the proportions of modern sports watches of that size. It's a beautiful combination of brushed and polished finishes, with many of the facets and curves that were a hallmark of Seiko design at the time.

The 6138-003 came with two bracelet styles: an angled oyster- style bracelet (export) and a fishbone- style bracelet (JDM). These bracelets are incredibly difficult to find individually, so make sure the watch you're buying comes with the original hardware.

Seiko 6138-004X "Bullhead"

Size	Motion	Thickness	Characteristics	Water resistance
44mm x 20mm	Seiko 6138	16mm	Day, Date, Tachymeter	70m

SEIKO 6138 "BULLHEAD" | PHOTO CREDIT @JEN.SEN71

The "Bullhead" 6138 is widely considered to be the most sought after model in the 6138 series. The "Bullhead" nickname is widely shared among many brands, and usually refers to chronographs with pushers placed on top of the watch case ( "Bull Horns" ). Although never actually adopted in modern watch cases, the design was intended to prevent the wearer from accidentally activating the chronograph while wearing the watch. I guess this wasn't really as big of an issue as they thought it might be.

The "Bullhead" was released in two main colorways: a brown version with a reddish-brown dial/bezel inlaid with gold subdials, and a black version with blue steel subdials and a black bezel. It's large, measuring 44 mm in diameter and 16 mm thick. This makes it one of the bulkiest watches Seiko has ever produced, so don't expect it to slip under your shirt cuff.

Like many other 6138s, this watch had two releases (one domestic and one exported). The "Sports-timer" (JDM) model actually differs from the export model in two main ways: the bracelet style and the presence of lume on the dial.

Finding one with the original bracelet can be tricky, and there are two variants to look for. The “JDM” version has a steel oyster -style bracelet engraved with “Seiko Speedtimer” , while the export versions had a fishbone bracelet engraved with “Chronograph Automatic” . Both variants were asymmetrical, meaning they had different sizes for the top and bottom lugs, and this can be an easy way to determine if the bracelet is original.

Seiko 6138-300X "Jumbo"

Size	Motion	Thickness	Characteristics	Water resistance
42mm x 19mm	Seiko 6138	15mm	Day, Date	70m

PHOTO CREDIT @JEN.SEN71

Although both the "UFO" and the "Bullhead" are larger than this watch on paper, the counterintuitive "Jumbo" actually appears the largest visually. The reason is that the dial itself extends to the outside of the case, and the lack of a bezel actually accentuates the size of the watch face.

The "Jumbo" has a clean, military-inspired design that uses yellow hands to accentuate the bold black and white dial. The subdials protrude slightly from the outer scale, which is also slightly raised, giving the dial a bit more visual dimension.

Of all the 6138 watch designs, the "Jumbo" may actually be the most classic, and looks similar to many of the designs Seiko still releases today. At 42 mm, it's also quite wearable, despite what its nickname might suggest.

Seiko 6138-700X "Calculator"

Size	Motion	Thickness	Characteristics	Water resistance
44mm x 19mm	Seiko 6138	14mm	Day, Date, Slide Rule	70m

SEIKO 6138 "CALCULATOR" | PHOTO CREDIT @GOLFSOHOL95

The 6138-7000, known as the "Calculator," is one of the most unique 6138 chronographs available. It features a double external bezel—one rotating and one fixed—for performing a wide variety of mathematical calculations. While digital calculators render it completely obsolete, performing these calculations mechanically is quite fun. Those familiar with using a slide rule should be able to operate the 6138-7000's bezels with little effort.

One thing that makes this model unique across the entire series is the use of acrylic glass instead of Seiko's proprietary Hardlex. Although Hardlex is much more durable than acrylic, plexiglass crystal was much more common in watches of this era and definitely adds to their vintage character.

It was only available in one color configuration, black and red, and is difficult to find on the used market. As a result, prices may be slightly higher for this unique iteration of the 6138.

Seiko 6138-802X "Panda"

Size	Motion	Thickness	Characteristics	Water resistance
40mm x 19mm	Seiko 6138	14mm	Day, Date, Tachymeter	70m

SEIKO 6138 "PANDA" | PHOTO CREDIT @SOMWATCHES

One of the most attractive vintage chronographs on the market, the 6138-8020 is arguably the perfect vintage chronograph . When making visual comparisons to the Chronomatic watch released by Hamilton during the same time period, this 40mm watch with contrasting black and white dials may be the most wearable of the bunch.

It's worth noting that there is also a "Baby Panda" model, marked 6183-801x. This version was also 40 mm, but had smaller subdials than its more popular sibling. However, this model is extremely rare, with most damaged and non-working examples on the market.

Panda watches are extremely popular among collectors, and the price of this particular one has risen rapidly over the years. Still, compared to the Hamilton Chronomatic or the Heuer Autavia, it's one of the most affordable classic panda chronographs.

Conclusion

Sometimes overlooked by serious collectors due to their affordability and ubiquity, there's no denying that the popularity of vintage Seiko chronographs is on the rise. While the 6139 line of single-register chronographs seems to get the most recognition, the 6138 dual-register chronographs are just as cool and make for a great everyday vintage piece.

These watches have fantastic designs, a true horological pedigree, and are common enough to keep prices relatively affordable. That makes the Seiko 6138 an excellent starting point for those looking to buy their first vintage chronograph. And if you follow a few common-sense rules, you should be able to find a piece that will serve you reliably for years to come.

Source: 60Clicks

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