This Week’s Featured Watch #79 – the Citizen Jet Monthly

Many people may be familiar with Citizen’s vintage ‘Monthly’ watches, which use the 5270 movement and were produced in the late 1960s. They are also found in the guise of the ‘Moon Dater’, which was the export model. However, Citizen produced a slightly earlier Monthly model, using the 4101 ‘Jet’ movement – and this model is much less known, and is a rare beast.  Made only in gold plated cases as far as I know, mine is of the white gold variety:

As can be seen this Monthly is part of the ‘Seven’ auto-dater line, using the 19 jewel version of the 4101 calibre. Unlike the 5270 monthlies, the month window is placed at the 9 o’clock position and is manually turned by the crown at 4 o’clock. The month wheel runs over the date wheel and is perforated so that the date can be seen through it.

The serial number shows production in August 1965, and ‘WGP’ refers to the case plating:

This is a large watch for its time, measuring 40mm across the case and the same lug to lug. It is also over 12mm thick, perhaps reflecting one of the reasons Citizen moved to the more compact oscillating weight movements for its automatics.

The size difference is more apparent when placed alongside a more conventional Jet model:

The 4101 movement beats at 18,000 per hour and can be manually wound, without hacking. The time is set by pulling the crown out one click, whilst the date is set by pulling in and out at the second click. The day is set by winding back and forth between 9 and 12:

It would have come in a box like this originally:

And finally a closer look at the dial and hands:


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This Week’s Featured Watch #78 – the 4-900014 Chronograph

One of two of Citizen’s chronographs with case number only, i.e. no model number, this is a single register ‘Challenge Timer’ model which is driven by the 8100A movement (‘A’ is for Automatic, there’s no ‘B’ version 🙂 ).  Both the twin register 8110A movement and the 8100 were introduced in 1972. As with the 8110, this type has 23 jewels and uses the central sweep hand as the second counter, whilst the sub-dial counts minutes. Otherwise its features are the same, running at 28,800 beats per hour with hand winding and ‘fly-back’ (instant reset and restart of chronograph function without having to stop it first).

This model has a steel case with black coated alloy bezel. Two dial designs were produced as far as I know, the other having a silver sub-dial – the black sub-dial on this example is rather more subtle. The case is polished – I believe this is correct since two models shown in a 1974 catalog show one with a polished case, the other with a satin finish:


The dial and hands create a very legible face, and the highlights on the sub-dial give some colour and interest. The case back gives a production date of May 1972, so this is an early one:


Good examples of the 8100 are not easy to find, rather like some of the lesser known 8110 models. Unlike the 8110 models, I don’t recall seeing any made after 1974, so they had only a limited production run and fewer will have been sold as a result.

For more information on all Citizen’s vintage chronographs, here’s a link to my reference page:



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Citizen 67-9011 (aka ‘Bullhead’) Original Day and Date Wheel Colour

Following my last post asking for help in researching original colours for the 67-9011 models, I think it’s time to publish my theory! I only got five responses to my questions, for which I am very grateful, so I guess this isn’t backed up by extensive data, but I think my theory makes sense. One of the people who replied has the same model I have which is pictured in the previous post, and like mine his has white Arabic / English day and date wheels – and we both believe these are original.

My opinion is that white day and date wheels were original to the 67-9011, for certain language combinations. At the moment this relates for certain only to the Arabic / English combination. This is supported by the part numbers for this model, where the date wheel has two alternative part numbers. If only black were original, then there would only be one part number. And this is backed up when other models are looked at – the 67-9119, the 67-9020 and the 67-9143 also have two part numbers and I know for sure that they were originally produced with black or white day/date wheels. The 67-9020 and 67-9143 are both ‘bullheads’ of course – the part numbers for them are the same as the 67-9011 so they must also be black and white options for that one. Here’s the relevant parts page from a 1977 casing parts catalogue, where you can see the dual part numbers for the ‘date dial’ listed for the relevant models:


I’m confident that this is a correct conclusion – all we need now is to determine whether there any white wheels used originally other than on the Arabic/English combo……

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A Question to Owners of the Challenge Timer (Bullhead) 67-9011

A question a visitor called Lawrence recently asked reminded me of something I have never quite got to the bottom of –  did the 67-9011 Challenge Timer, commonly known as the ‘Bullhead’, originally come with white day and date wheels, or only with black day and date wheels? Now this may seem a somewhat geeky bit of detail, and not exactly the ‘meaning of life’, but if I can answer this question I can add it to my guide to buying an original piece. I have my own theory about it, but I’ll keep that to myself for now 🙂

So, if you have what you believe to be a fully original example, I would like to know (a) what the colour of the day & date wheels are, (b) what the day wheel language combination is – this may give a clue to my theory! – and (c) what is the dial colour (i.e. one version had a black or grey dial and a printed, not applied, Citizen logo).

Although there are other versions of the ‘bullhead’ with the same case design, to keep it simple, at least for now, I want to stick to the most common 67-9011 model, with one of the following case numbers: 4-901177, 4-901053, or 4-901011. In the catalogue images I have of these models, the day and date wheels are black……

Here’s one of my examples of case number 4-901177 – as you can see it has white wheels, and the language combo is English and Arabic:


It will be great to hear from anyone with an original piece – please remember to answer all three questions and use the comment facility for this particular post for your answers.

Thanks in advance!

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Citizen Cosmotron GX – SOLD

I’m offering one of my Cosmotron GX’s for sale – head only. This one, case number 4-370601, has a textured green dial with white chapter ring. The dial and crystal are in good condition, and it has a Kanji only day wheel :


Although the GX is a ‘Cosmotron’ it is in fact a tuning fork movement – a ‘hummer’ – rather than an electro-mechanical hybrid. These were not made for very long, and this one dates from October 1975:


The 11 jewel 3701B movement is Citizen’s own design (so, unlike the 3701A, is not marked ‘LIC. BULOVA’ ) although it is of course very similar to Bulova’s single coil 219. The watch is in good working order, keeping accurate time and the date and day set correctly. The day is not quick-set, so it’s advanced by turning past midnight when the crown is out one step, which also ‘hacks’ the movement. The date is advanced with the crown fully in, in the normal running position.

The movement stops properly when the crown is pulled right out, which switches it off and conserves battery power when not in regular use.

The case is in decent condition with some light scratches and marks, but no major dings. Case diameter is about 38mm, with 18mm lugs (despite the 20mm strap shown in some of my pics!) – here are more images of the watch from my ‘Featured Watches’ series of posts:

Price is GBP135 (USD190), which, to make it simple, includes shipping. Payment to be via PayPal only.  I am in the UK and shipping will be via Special Next Day Delivery within the UK, or International Tracked (& Signed if service is available) so please check that tracking is available in your country here first:

Please contact me via the ‘Got a Question’ Contact Form – see top of the right-hand panel on the home page. Thanks.

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Two More Speedy’s Added….

……to Brian’s 67-9313 Speedy Restoration page 🙂  They are numbers 18 and 19.

It’s cool to see the population of ‘Speedy’ models passing through Brian’s hands. Of course service and repair of these fine 8110a calibres is not cheap, but with the increasing value of these pieces – and perhaps particularly the 67-9313 – as reflected on auction sites, my view is that it is a sound investment. One of the Speedy’s Brian serviced recently sold for $1200, and a search of eBay shows that far from perfect ones sell for decent money. The added value of a master watchmaker’s service is considerable, as well of course as getting the peace of mind that your watch has been properly cleaned and lubricated.


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Not Seen This Model Before….

One of the joys of collection and researching Citizen’s vintage watches is that you can be sure you’ve not discovered everything! Just the other week, ‘Martin’ visited my blog and, as many visitors do, asked for more information about his watch…

Martin kindly sent photos, and with his permission, and with full credit to him for the images, he asked me about this:


Although I’ve not seen this watch before, the quality of  the dial, for example the fine printing and the applied logos, suggest to me that it is an authentic model. The 23 jewel movement is also in good order and is marked as a 5270, usually found in Seven Star models, as reflected in the ‘7’ crown logo on the dial:


But the most intriguing part of the watch is this case back:


So far in my experience, this is a unique design – and I believe it is an authentic one, given the quality of the markings and the information it provides. The movement number is present, along with ‘-71’ which I reckon is the production year. That fits with the use of ‘proof’ since that term was used until around 1973 when ‘resistant’ became the norm. The 000226 serial number suggests to me low volume production, which might well explain why I’ve never seen one of these before! The nicely stamped eagle motif in the centre is pretty much the same as the Chrono Master dial emblem:


Finally, the back is stamped with ‘HMC’, which I have seen occasionally before on several watches. I have never fully got to the bottom of its meaning, but my best guess is that it relates to Citizen’s Korean casing and assembly factory, which was acquired in the early 1970s – and was known as the Hanmi Citizen Precision Industry. Here is an exceptionally rare Chrono Master case back I spotted some years ago:


So here we have it – a ‘new’ vintage model, in my opinion at least 🙂

Thanks again to Martin for allowing me to post about his watch and for his photos.

Comments welcome!

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