Citizen’s Case Numbers – the Mysterious Case Number Letter

A change today from a watch feature to something that’s always been a bit of a mystery – the letter stamped at the end of Citizen’s case numbers. Although not needed as a part number since the case number alone, e.g. 4-123456 provides that, I have never pinned down just what the additional letter indicates. I wrote to Citizen Japan about it – didn’t get a reply! So I’m left to my own theory 🙂

Most vintage Citizens with the above case number format, typically from the late 1960s and on through the 1970s have ‘TA’, ‘K’ or ‘Y’ stamped alongside the case number:

My theory is that these letters are factory codes – relatively recently I got hold of a scanned catalogue from the early 1970s, and that includes a list of factories:

My best guess is that ‘TA’ is the Tanashi or Tama Seimitsu factory, ‘K’ is the Kawaguchiko factory (dials were made there and dial codes often include ‘KA’ too), and ‘Y’ is …… not so obvious! You can see as well the ‘Star’ Seimitsu Company – older watches have ‘STAR’ marked on them since they initially made cases for Citizen, but later produced smaller parts, particularly screws.

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Today’s Watch – Citizen Cosmotron GX

Today’s piece is another battery powered model, and although it’s a Cosmotron, it’s something of an anomaly. Unlike any other Cosmotron this one does not have a magnet driven hairspring – in fact it is a ‘hummer’ – a tuning fork watch. I don’t know why Citizen branded this as a Cosmotron – my only theory is that the design of the single coil 3701B movement was their own, and not made under licence from Bulova as was seen with their Hisonic range. There’s no mistaking it’s a hummer either – it hums very loudly, and is not the best thing to have on your bedside table if you want a good night’s sleep! I’m not a great lover of roman numerals on watch dials, but they work well on this one in my opinion. The finely printed black hour markers contrast well with the clear white dial (not very well shown in today’s photo), whilst the slender hands also have a fine black centre line – it’s a very smart look. The GX is a fairly rare watch, so a nice one to add to any collection. This one is from November 1975:

More on this one here:

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Today’s Watch – Citizen’s First Quartz, 8811

Today’s watch was a very significant one for Citizen – launched in mid-1973 it was their first quartz model. Using the 8810, 8811 and 8821 movements, they were electro-mechanical calibres, like the Cosmotrons before them. In other words they were battery powered, with a quartz crystal regulating a magnetically driven balance wheel via mechanical gears. The result is a remarkable 115,200 beats per hour oscillation, and accuracy for the 8811 & 8821 variants of +/- 10 seconds per month, and just +/- 5 seconds per month for the ‘EFA’ 8810. These hybrid movements were soon replaced by full electronic movements – I have read that they may have been produced for little more than 6 months. They are rare, especially the EFA models, and are high quality pieces – they were very expensive to buy new. They all have a ‘jewel’ at the 12 o’clock position, with two more at 6 and 9 o’clock on the EFA version. Mine is from October 1973 and is one of the 8811 models:

This is the range of models, from a 1974 catalogue

And the movement:

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Today’s Watch – Citizen X8 Chronometer

Continuing with the electric theme, today’s watch is a rare Officially Certified Chronometer version of the electro-mechanical X8 line. The 0820 movement runs at 21,600 beats per hour, has 19 jewels and mine is uniquely numbered X00294. The case is a very unusual shape, and I think it is unique this model. Mine was made in August 1970:

More on this one here: (NB I refer to this one and the titanium cased X8 as the only two chronometer grade X8’s – there was in fact one more model, not (yet anyway) in my collection.

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Citizen Parawater – The Oceanic Tests

There’s a change today from my daily and weekend watch features, since a new video documentary has just been published about Citizen’s testing of their parawater automatics in the 1960s. And I want to leave this post at the top of the home page for a couple of days. You may know that Citizen put their parawater system to the test with a campaign of releasing Jet Automatic watches into the Sea of Japan and the Pacific Ocean, using special buoys to hold them. I was very happy to provide some of my reference material to help in the production of the video, so rather than my usual watch post, I would invite you to take a look at the Italian language video here:

I am very impressed with the quality of the film – it’s a shame my Italian is very limited since I would love to follow the narration. It is a very professional piece of work.

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Today’s Watch – Citizen Quartz 8600 ‘Blinker’

Citizen moved into quartz technology in a big way in the early 1970s, and their early quartz models are high quality pieces, designed to be serviced, and used for many years. They are collectable things as a result and a few in particular have extra features that make them a little more desirable. And today’s piece is one of them – with the 8600A movement inside it is a ‘blinker’ – a small LED lamp at 12 o’clock flashes every 60 seconds. Rather like the Cosmotron Special, the button at 8 o’clock enables accurate time synchronisation and with a +/- 10 seconds accuracy per month this was of course far more accurate than any mechanical piece at that time. As well as the nice applied CQ logo, my example is marked ‘QUARTZ’, so it’s an early one, since from around October 1974 they were marked ‘Crystron’. It was produced in August of that year, and is running very well, including the LED flashing every minute:

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Today’s Watch – Citizen X8 Chronometer, Titanium

Citizen was the first company in the world to make a watch case fully from titanium. Although common these days, manufacturing challenges made it difficult to work with in the early 1970s. Citizen made and sold less than 2000 of this X8 model, all of which I believe were produced in May 1970. Using the 0820 movement, it is an Officially Certified Chronometer measured against the Japan Chronometer Association’s standards at the time. The 99.6% titanium case is a dull grey, not polished like many watches typically seen today:

You can find more info on this model here:

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Today’s Watch – Citizen Cosmotron, 4-480279

Another Cosmotron today, and one of the more unusual ones – the movement is the 4840 date only version of the 0840 calibre. The unusual bit is the crystal, since it has the ‘Citizen Electronic’ logos and minute markers printed on the inside and not on the dial itself. The plain black dial just carries the applied Cosmotron motif, along with nicely shaped hour markers. Although my example is not in very good condition, these are rarely seen so I grabbed it when I could. I suspect a replacement glass would be rather hard to find! This is one of the middle generation of Cosmotrons, running at 21,600 bph, before the 78xx series replaced them, and was produced in November 1971:

More info on this one here:

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Today’s Watch – Citizen Cosmotron Special

I think we’ll have an electric week this week – starting with the last in the line of 7800 calibre Cosmotrons, the Special version. The Special, calibre number 7803, is immediately identifiable by the button at the 8 o’clock position, which enables accurate time setting of the seconds and minutes hands, i.e. it not only zeros the second hand (to 12 o’clock) but also the minute hand when it is within + or – 3 minutes of 12 o’clock. The quality of many of the Cosmotrons is high, and particularly so on the Special variants. This example is from August 1973, and is an all stainless steel model with a ‘tv’ style case. The white dial features smart polished steel markers and hands, highlighted with slender black centres. There is no ‘X8’ on these later models, with ‘electronic’ printed beneath the Citizen mark and an applied Cosmotron logo above the 6 o’clock marker. The second hand is characteristic of the Cosmotrons, with its coffin shaped tail. The solid link bracelet is a familiar design also seen on a number of the 8110A automatic chronograph models. The case and bezel are generally polished, but it has brushed lug ends to match the bracelet:

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Today’s Watch: Citizen Master, 19 Jewels

Today’s hand-winder is the Master, made only in 1959 as far as I know and was the last in the long line of what Citizen called its ‘Center Second’ watches. The 910/913 19 jewel movement was a higher grade version of the Junior seen yesterday, and was marked as having three adjustments at the factory. Unlike yesterday’s 9 jewel movement the Master does have the para shock system introduced by Citizen in 1956. Good examples of these are hard to find, due no doubt to their very short production run. The dial on mine is not so good, although the case has worn well:

More info on this watch here:

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