Vintage Seiko Bullhead 6138 Experience

This is the second contribution by Jude, after his excellent first post on a Glycine. This time, we examine a vintage Seiko, which is not a topic I usually write about. Jude is going from strength to strength with his second post!

Today I am going to share on a very popular vintage Seiko model, the Seiko 6138 Bullhead. This model has been written about many times, and was also on Hodinkee. Incidentally, this was also one of the first few articles on vintage Seiko chronographs that raised my awareness of this watch, and eventually buying it. Since this watch has been written about quite a fair bit, I will not go into too much details about the watch and instead come more from the perspective of a collector, and some lessons learnt from the experience. (Disclaimer: Some parts of the watch are aftermarket parts, but this post is more to share the experience. Will cover the intricacies later.)

Seiko Bullhead 6138

Seiko Bullhead 6138


Before that, allow me to start with a brief perspective of the watch. This is a 1970s Seiko chronograph powered by the 6138 movement. The 6138 movement came in the period just after the very important year of 1969 for automatic chronographs. You can read more of this period of horology here if you have not yet read of it. This article puts this period of horology and the various brands and technology in perspective very well.

For Seiko, this 6138 movement came in later than the 6139 movement. The 6139 was arguably the first automatic chronograph movement in the race for the first automatic chronograph. (Note, arguably.) For a movement that came a little after 1969, this movement is rather state of the art. Many watches in the period were still having 1) no quickset for dates; 2) difficult ways to change the day date. Comparatively, the 6138 movement is a column wheel vertical clutch chronograph with 2 sub registers, and a very easy to adjust day-date function. For a vintage watch to be worn in modern times, some might find it difficult to do manual or quickset of the day/date in some of the watches from that time period. In terms of purely technical specifications, however, I would rate the Citizen automatic chronographs higher, but this comparison will be reserved for another time.

First Impressions

Some thoughts on first impressions. This watch is very visually attractive. It is big for vintage proportions coming in at around 42 to 43mm. It comes with a very Speedmaster-like design. This is the blue variant with black dial and blue sub dials. The colour combination is very attractive, striking, and very modern. I really love the whole look of it.

Seiko Bullhead 6138

Seiko Bullhead 6138

Another observation was how thick the watch is. The thickness is about 15mm so it sits really high on the wrist. This makes it impossible to fit it under the cuffs. On the wrist, I really love the look, but the massive thickness creates a toppling effect on the wrist due to the weight and the height of the watch. With a 42-43mm dial and a 15mm height, It is like a cylinder which is tall but has a small bottom, creating a toppling effect on the wrist. The thickness also makes it a scratch magnet. Third impression, the finishing on this watch is rather exceptional. I am not sure how much this cost in 1970s, but the steel feels great, and the finishing alternates between brushed and polished, just look at the following pictures:


Seiko Bullhead 6138 – Alternating polish on side of the case

Seiko 6138 Bullhead - Contrasting finish

Seiko 6138 Bullhead – Contrasting finish


Seiko Bullhead 6138 – Top of case. Observe the thickness.

Learning Points

After the brief introduction and the run through on the looks, I would like to share my personal Seiko Bullhead experience. This watch was my first vintage watch purchase. I was very excited after reading so many articles on the Seiko Bullhead and decided that this was THE WATCH to buy. A deal was soon made and I was the proud owner of the watch. It was an exhilarating feeling and it kickstarted my journey into vintage watches. This watch has helped me to make several good friends in this watch collection hobby, and I have also learnt a few points which I will put in point form below:

  • Beware of frankens

If you are the sort that cannot stand even one un-original/aftermarket part, please read up on the watch first. There is a fantastic guide from this site. Another way is to leverage on the knowledge of your friends, or experts on the internet. I think there is definitely a circle of collectors (forums, hobby groups, friends, etc) so just try to find them and seek their advice and comments if you are really unsure. They will be able to give you some advice from a quick glance, saving you hours and hours of read up. You can also try letting watch repairers or experts in the field verify the authenticity for you after you have purchased it. Some vintage shops might be nice enough to give you their two cents worth of expert opinions on your piece if you are on good relationships with them. I will also share some quick points that I have learnt after buying this watch.


Firstly, look out for the dial as there are tons of aftermarket dials for Seiko Bullhead nowadays. For the blue variant (some calls it the black variant), there should not be the ‘Speedtimer’ words on it. Blue variants should only show ‘Seiko’, ‘Chronograph’, ‘Automatic’ in that order vertically (see second pic below). ‘Speedtimer’ wordings are only for the brown variants.

Seiko 6138 Bullhead - Dial text

Seiko 6138 Bullhead – Dial text


The hands at the 2 sub dials should be white for the blue variant. My hands should have been taken from the brown variant. Note that the sweeping seconds hand for blue variant should be yellow.

Another thing to note is the design of the sweeping seconds hand. The right sweeping seconds should be thicker at the point pivoted to the centre screw and tapered down to the edge of the dial. If you look at the picture below, the sweeping seconds hand looks almost straight, which is wrong. This straight seconds hand is a common aftermarket part so beware because it is aftermarket and it looks very off on the watch. Actually, nowadays there are aftermarket hands (see other pic below) that are really done with the right design, so I am not sure how to differentiate as well if it is so well mimicked. Maybe mine could be aftermarket hands since it looks rather good condition.


Picture taken from the internet


Picture taken from the internet


Movement wise, make sure that the seller opens up the movement to show it to you, even though this is very technical and it is very hard to verify (personally, I am not at that level yet). While it is unlikely that the movements can be swapped entirely, the interchangeable parts of several parts from the 6139 Seiko movement makes it highly possible for a repairer/second hand seller to replace a part from 6138 with one from 6139, and vice versa. For my case, my 6138 plate underneath the rotor was swapped. If you look at the pictures below, you will notice the similarities between 6138 and 6139 movement and why the parts can be interchangeable.

Replacement of parts could also be possible with other Seiko movements. Take a look at this article for an example where a 6119 stem was used in the 6138.


My bracelet is actually a ‘Speedtimer’ bracelet. Since there are no blue variant that are ‘Speedtimers’, this bracelet is non-original to this watch. The ‘Speedtimer’ bracelet should only be fitted on brown variants with the ‘Speedtimer’ wording on the dial.

The correct bracelet for a blue variant like mine should have been a fishbone bracelet instead.

Characteristically, the ‘Speedtimer’ bracelets have ‘Speedtimer’ engraved on the clasp. It is also thicker at the lugs and tapers down to the clasp



Speedtimer signed clasp

Speedtimer signed clasp

  • Sourcing

Do not worry about scarcity. This watch is not that rare. However, it is extremely popular and this leads to more frankens (point 1). Since my purchase, I have seen at least 4 more chances to buy this watch at around the same price point. It comes out from time to time on forums, carousell, and ebay so just keep a look out for it. Try to buy from a circle of collectors as the prices are usually better, watches are better, and with lesser aftermarket parts.

I am based in Singapore and locally, 90% of the Seiko Bullheads I see around has at least 1 aftermarket part (usually the hands), so do take note if you are buying locally. Choose a reliable seller/shop and buy the buyer before purchasing the watch itself.

  • Functionality

My first purchase was actually from another source and the watch hand an issue whereby the minute register on the left keeps recording time even when you have done the start, stop and reset. This might have been due to the separation of the axle from the gear on the minute register wheel and hence the minute register wheels becomes permanently engaged. This was also recounted from the website that I had shared earlier and another source here. Thanks both authors for the detailed technical explanation. Is this a functional weakness in the 6138 calibres? I am not sure but at least I know I am not alone. Since then, I have swapped watches and got hold of my current pair.

In general, vintage chronographs are extremely problematic so do try to test all functions in person if it is possible. They are pieces from 40 odd years ago after all.


Overall, it is a very nice watch. On the positive side, I managed to get hold of a highly sought after watch, made a few good friends with it, and functionally, it is perfect and keeps great time. On the minus, I had purchased a watch with many aftermarket parts. While the price I paid was after factoring all these into account, you cannot deny that there is some sense of disappointment in having a sample that is not fully original. I still wear it from time to time as it is a rather nice piece on the wrist, but if the chance arises, I might switch it out and get in some cashflow. The thrill of the hunt has since mellowed and strangely, once it is in your collection, you tick off an imaginary box and start hunting for the next piece. Alas, the slippery slope of watch collections.

11 thoughts on “Vintage Seiko Bullhead 6138 Experience

  1. Hi, I am currently on the hunt for one of these black dial bullheads. It has come up a number of times I am not factoring the cost of service. I was wondering if you could give me a sense how much it would cost to service/check the watch upon purchase and then to regularly service it? Thanks, you article is outstanding! -Lee

    • Hello,

      The cost of servicing always depends on the condition and availability of parts. It would be best if you buy a decent working sample within your budget and get an estimate from your regular watch guy. I won’t be surprised if an overhaul costs between SGD 100-200. A repair job would costs more of course.

      If possible, I would ask for an amplitude reading of the watch in at least 2 positions before purchasing.

  2. May i ask whether you know any place to get the newer series of Seiko Bullhead? Models SCEB009, 011, 013 or 015. Cant seem to find any shop that bring in these JDMs. Appreciate if you could offer some advice where to get one locally in SG. Thanks in advamce.

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