Seiko 6138 Vintage Chronographs Guide

Warning: you may develop a new addiction after going through this article.

I must admit that I am familiar with this addiction because my love for vintage Seiko’s started with the acquisition of a beautiful blue 6138 “Kakume” model. 6138 is one of the several chrono calibers developed by Seiko in the 70’s. And if its older brother 6139 was the first one to be released, the 6138 dual register movement arguably equipped some of the most emblematic models from this era. The objective of this article is to give you an overview of available models, without going into details such as hands variations, dial codes or caseback references. These details will be available in model-specific buying guides. We also mention approximative current market prices for watches in good vintage condition.

Without further ado, let’s dive in. You’ll find technical characteristics of this mechanical masterpiece at the end of the article.

6138-001X: UFO or Yachtman

Nicknamed UFO because of its lugless weird-looking case, this watch features a black dial, two silver sub-dials (one being slightly bigger than the other) and a red and black tachymeter scale.

The UFO was made for both the Japanese domestic market (“JDM”) and the international market. We have a full reference guide where we’re going through all available variations. Check it out if you’re interested in this model.

Market price: expect to pay ~$500 for a UFO.

6138-0020: Tokei Zara

Seiko 6138-0020 Tokei Zara

Tokei Zara (bowl) was destined for the domestic market only and exists in two color variants: with a blue minutes sub-dial and with a grey minutes sub-dial. Housed in a remarkable “helmet” case with a very nice mix of brushed and polished surfaces, the Tokei Zara is quite a rare guest on Western wrists.

Market price: Tokei Zara can still be found for roughly $400 – $600 (not for long in my opinion).

6138-003X: Kakume

Kakume means square eyes in Japanese and it’s easy to see why this bright watch has been nicknamed this way: its hour and minute sub-dials are square. The dial is either blue or champagne in color. The blue version was distributed in Japan and internationally (thus the dial can be found with “Speedtimer” or “Chronograph Automatic” markings), whereas the champagne version was made for the JDM market only.

The champagne dial is considered significantly rarer.

Update: we recently published a full reference guide about the Kakume. We explain all the subtle dial & hands differences that you may encounter when attempting to buy this model. Check it out!

Market price: Kakume in good condition currently costs $500 – $750 (blue dial) and $750+ (champagne dial).

6138-004X: Bullhead

This massive chronograph (44mm) owes its nickname to the position of its crown and pushers. It’s a pity that there are very few bullhead chronographs produced today, as these vintage models from Seiko (and also from Citizen – the Seiko’s eternal competitor produced some amazing bullhead chronographs in the 70’s) have a lot of charisma and have become very collectible.

Two color schemes were used: one with a brown dial and golden sub-dials, and one with a black dial and blueish sub-dials. The Bullhead is one of the most faked / franked models, beware.

Market price: expect to pay between $600 and $850 for a nice-looking Bullhead.

6138-300X: Jumbo

Thanks to its very large multi-level dial, the Jumbo has an amazing wrist presence. Yet, perhaps due to its too classic looks, it is somewhat overlooked by collectors who prefer more original models such as the ones presented above. This model, available with a black or a dark blue dial, remains one of the more affordable watches housing the 6138 movement.

Market price: it’s still relatively easy to find a Jumbo for under $500.

6138-700X: Sliderule or Pilot Calculator

Housed in a case similar to the UFO, this rare 6138 Sliderule looks even larger and is unique in a lot of ways. It features a double bezel, one of them being rotating – it’s the only watch with a rotating bezel in the 6138 range. Furthermore, it is equipped with a plastic pointer which is needed to perform some mathematical calculations. And, to finish with, it comes with an acrylic glass (all the other 6138 use hardlex). It’s very difficult to find this watch in good condition as its large bezel is prone to scratches.

Market price: current prices for a Slide Rule / Calculator are approaching $1,000.

6138-8000: Baby Panda

In my very personal opinion, this is the most desirable model in the lot. Baby Panda is a timeless chronograph suitable for every occasion. And if you want some variation to its ivory face, you can try hunting down the Reverse Baby Panda, sporting an amazing deep grey dial.

Market price: Baby Panda’s are rare and usually exceed $1,500, and even $2,000 for black dial models.

6138-8010: Holy Grail

Seiko 6138-8010 "Holy Grail" / Source: sg.carousell.com

This model made exclusively for the Japanese domestic market may very well be the rarest one of the lot. Sometimes called “holy grail” because it shows up just a couple of times per year on auction sites, it doesn’t have a proper nickname. With a perfectly-sized case at 42mm and a striking blue dial, it can fetch a hefty price. Especially if the original bracelet, specific to this model, is included.

Market price: at least $1,500.

6138-8020: Panda

All-time favorites among Seiko collectors, original white Pandas in good condition are becoming a rare sight. Pay attention to the condition of the case (it may be over-polished), and be aware that its dial is often faked. Unfortunately, the quality of fakes is getting better and better, thus usually it’s a good idea to “buy the seller” when buying used timepieces, especially with watches costing 4 figures.

There are two variations of the Panda that are somewhat less common (but also less popular). Both feature a black dial with golden elements and white hands. It can come in a gold-plated case or in a stainless steel case with assorted bracelets.

Market price: consider yourself lucky if you catch an original and unpolished Seiko Panda for less than $1,200.

6138-8030: Baby Kakume

Last but not least we have the Baby Kakume which, as its name suggests, features square eyes / sub-dials in a slightly smaller, 40mm case. Three different color schemes were released: Blue, Gold in stainless steel case (also known as “John Player Special”) and Gold in gold-plated case.

Market price: $400 – $700 can land you a decent Baby Kakume.

6138: Presentation of the movement

Let’s finish this article with a few words about the Seiko in-house movement powering these beautiful watches. The 6138 is a dual-register (minutes, hours) chronograph that Seiko released shortly after the 6139 movement (which was one of the first automatic chronographs in the world). It’s automatic, can be hand-wound, and has a quick-set function for both day and date. Impressive array of features for a mechanism designed 50 years ago!

Running at 21,600 beats per hour, it has two variations: the 6138A and the later 6138B with a modified switching mechanism. The 6138A has 21 jewels and the 6138B either 21 or 23 jewels, depending on the model. Here are a couple of pictures of the machine with and without the rotor:

Seiko 6138 automatic chonorgraph movement, with and without the rotor

Wrapping up

I hope you enjoyed this short overview of vintage chronographs powered by Seiko 6138. Perhaps you even fell in love with one of them? The good thing is that most of them are still available under $1,000 in good condition. I can only see them going up in value, so it may be a good idea to add this iconic chronograph to your collection.

Which is your favorite model? Add a comment below, and feel free to include a picture if you already own one!

Further reading : check out our vintage Seiko reference guides

• Seiko 6138 “Kakume” Reference Guide
• Seiko 6138 “UFO” Reference Guide

Vintage Watch Inc

Dennis is the founder and editor of Vintage Watch Inc. Passionate about Soviet and Japanese vintage timepieces and a finance professional by day, he proudly wears a Seiko Pogue with his suit.