# Citizen Xz8 Cosmotrons



## Morris Minor (Oct 4, 2010)

I've just published a page on my blog about the electro-mechanical watches Citizen produced for a short while in the late 60s/early 70s. Once I came across the X8 Cosmotrons as they are known, I just had to find out more...

http://sweep-hand.org/

Stephen


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## Oliverb (Sep 3, 2012)

Not the worlds first electronic watch. The Bulova Accutron, introduced in the Fall of 1960, had a transistor and a resistor. The Accutron has the honor of being the oldest example of an electronic device still in continuous use.


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## Chascomm (Sep 9, 2005)

Oliverb said:


> Not the worlds first electronic watch. The Bulova Accutron, introduced in the Fall of 1960, had a transistor and a resistor. The Accutron has the honor of being the oldest example of an electronic device still in continuous use.


I understand what Stephen is asserting is that the Citizen Electronic was the first use of a transistor in a balance-wheel movement. For clarity and context it would probably be worth adding a mention of the Accutron.

But my question is whether in fact Citizen can claim to have produced the first balance-wheel/transistor watch. It would be fairer to say that they were the first to bring it to market. Omega apparently prototyped this concept:

http://electric-watches.co.uk/make/omega/balance/balance.php

and I understand that the watch worn by Pavel Belyayev on the Voskhod-2 mission used a transistor-switched balance-wheel (although I have not yet any hard evidence of that).


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## Chascomm (Sep 9, 2005)

From Doensen's book:

"*Transistorised system with balance*

The first point-contact transitor was invented by John Bardeen and Walter Brattain at the Bell Telephone Laboratories in the United States in December 1947 (See: The Physical Review July 15th 1948 and patent 2.623.102 USA). W. Schockley did the basic research on the P-N junction and in 1950 R.N. Hall developed an alloy-junction transistor. It took fifteen years until transistors were made available by the manufacturers, small enough to be incorporated in a wrist watch. The tremendous problems caused by sparking and eroding of the mechanical switch-contacts were now solved.

The transistor can be used as an amplifier as well as an electrical switch. In these watches it has a switch function. When the voltage of the base of a NPN transistor becomes positive or the voltage of the base of a PNP transistor negative, the transitor will conduct the electrical current and will close the circuit. The current flows through the drive or impulsing coil, the coil becomes a magnet and the balance receives an impulse in the way that has been described in the previous chapter. The voltage to steer the base of the transistor is generated by induction in the phase or trigger coil. The coil that can be detected in these watches consists, in fact, of two coils wound up together. When the two coils on the balance pass the fixed magnets, one coil, connected to the base, generates an induction voltage, the base becomes negative or positive and the transistor conducts the current at the same time. The driving coil gives the balance an impulse. When the balance swings back, the trigger coil generates an opposite voltage and the transistor will stay closed. Thus, the balance is given an impulse in the same direction each swing. This system was invented by Etablissements Leon Hatot (ATO) in the early nineteen fifties (patent no. 1.090.564 and 1.092.411, France 1953). This patent is used in millions of watches, manufactured by factories all over the world. Often a stamp on the pillar plate can be detected indicating: licence ATO or lic. ATO.

At the meeting of the French Horological Society in Paris on November 24th 1956, Leon Hatot presented a prototype of an electronic wrist watch with rewinding motor and a transistor instead of mechanical contacts.

The first commercial wrist watch with a transistor was the 'Bulova Accutron' caliber 214. These watches have been dealt with in the chapter about tuning-fork watches.

The first one with a spring-balance and a transistor was the 'ESA 9150', the 'Dynotron'."

"*ESA 9150 Dynotron*.

Oscillation frequency 3 Hz. A watch with date-indication.

1962-1967 Many tests are carried out and a large number of chronometer certificates obtained.

1967 A limited quantity has been marketed by ESA.

1968 Production in large quantities starts to take place."

and on Citizen, he says:

"*Citizen*

The first working prototypes were ready in March 1966 and were presented to the press at the Osaka Fair of 1967. The Citizen X-8 Cosmotron was the first Japanese electronic watch. Its distinctive features are the four magnets on the balance and a single coil fixed on the pillar plate. Frequency 6 Hz.

Citizen X-8 Chronometer cal. 0802, 0802, 0884. Chronomaster cal. 0820. Chronotron cal. 0840 and 0880. Date cal. 4840 (1969). Caliber 0811, 0830, 4830.

The Bulova Caravelle 12 OTC is the same movement as the Citizen 0811, the 12 OUC as the 0830, the 12 OUCD as the 4830.

Citizen 5600 series, 1969. Caliber 5620 and 5650. Citizen IC 12 The Citizen 5800 series, the IC 12, 1970. Frequency 12 Hz.

5800 IC-12 Chronometer.

5810 and 5835 IC-12 Cosmotron with centre second.

5820 and 5830 without centre second. The movement has eight magnets fixed on the balance-wheel, two coils fixed on the pillar plate. This was an incredibly fast beating watch and the smallest transistorised ladies' watch at that time. Citizen 7800 Cosmotron, 1972. Four different calibers exist: 7800, 7801, 7803 A and the 7804 A. When the watch is held upright, date correction becomes possible, while held upside down day correction is possible. Frequency 6 Hz. "

http://doensen.home....l/contents.html


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## Silver Hawk (Dec 2, 2003)

Chascomm said:


> Oliverb said:
> 
> 
> > Not the worlds first electronic watch. The Bulova Accutron, introduced in the Fall of 1960, had a transistor and a resistor. The Accutron has the honor of being the oldest example of an electronic device still in continuous use.
> ...


Yes, in this X-8 blog, Stephen is only referring to balance wheel based watches....not tuning fork watches. It certainly is confusing....I still refer to LIP (R27) as the first maker to bring an electronic balance-wheel watch to market....electronic because it has a diode to reduce sparking across its contacts....but no transistor in the R27 and R148/184 LIP movements.

And how are we gauging "first"? I think the only fair way is to use "first to market" as there must have been many research projects by many movement manufacturers, some of which we probably still no nothing or very little about.


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## Morris Minor (Oct 4, 2010)

Interesting info in reply to my post 

Maybe I've summarised what Citizen claim too much - this is what is stated in their tech guide on the X8. It's described as: *'the world's first genuine electronic wristwatch that has adopted a moving-magnet type balance motor, driven by transistor on the regulating device'*

I'll add this to my page now to clarify the claim - but I'm also interested in what you make of it, since I'm not familiar with other makes and their history,

Stephen


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## Silver Hawk (Dec 2, 2003)

BTW Stephen.....and big :thumbsup: to your blog.


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## Morris Minor (Oct 4, 2010)

Silver Hawk said:


> BTW Stephen.....and big :thumbsup: to your blog.


thanks Paul - please let me know if you see anything that needs correcting / adding to 

Stephen


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## Silver Hawk (Dec 2, 2003)

Hmmmm.....reading between the lines, it seems Citizen were first to develop but ESA first to market .... a transistor controlled balance-wheel movement



Morris Minor said:


> *'the world's first genuine electronic wristwatch that has adopted a moving-magnet type balance motor, driven by transistor on the regulating device'*





Chascomm said:


> From Doensen's book:
> 
> The *first commercial wrist watch* with a transistor was the 'Bulova Accutron' caliber 214. These watches have been dealt with in the chapter about tuning-fork watches.
> 
> The *first one with a spring-balance and a transistor* was the 'ESA 9150', the 'Dynotron'."


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## Morris Minor (Oct 4, 2010)

Silver Hawk said:


> Hmmmm.....reading between the lines, it seems Citizen were first to develop but ESA first to market .... a transistor controlled balance-wheel movement
> 
> 
> 
> ...


Thanks Paul - '*moving-magnet type balance motor' *- could it be this bit that was a first, in combination with the transistorised regulation? I see that Doensen says that was a 'distinctive' feature.

Stephen


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## Silver Hawk (Dec 2, 2003)

Morris Minor said:


> Silver Hawk said:
> 
> 
> > Hmmmm.....reading between the lines, it seems Citizen were first to develop but ESA first to market .... a transistor controlled balance-wheel movement
> ...


Possibly... although all the ESA Dynotron movements are "moving magnet balance wheels" types, as are the Junghans 600 and the Seikos 370 etc.


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## Morris Minor (Oct 4, 2010)

Silver Hawk said:


> Possibly... although all the ESA Dynotron movements are "moving magnet balance wheels" types, as are the Junghans 600 and the Seikos 370 etc.


Ah, right  My edit of my blog page now says this is Citizen's claim about the watch, rather than me asserting it.

Stephen


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## Morris Minor (Oct 4, 2010)

Should have said in last post that Citizen say the X8 was 'released' (on-line translator) in 1966 with a retail price of JPY32,000,

Stephen


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## Chascomm (Sep 9, 2005)

Silver Hawk said:


> Yes, in this X-8 blog, Stephen is only referring to balance wheel based watches....not tuning fork watches. It certainly is confusing....I still refer to LIP (R27) as the first maker to bring an electronic balance-wheel watch to market....electronic because it has a diode to reduce sparking across its contacts....but no transistor in the R27 and R148/184 LIP movements.
> 
> And how are we gauging "first"? I think the only fair way is to use "first to market" as there must have been many research projects by many movement manufacturers, some of which we probably still no nothing or very little about.


Paul, that's a good point about the diode relay as 'electronic' although to be fair in that arrangement the contact switch has not been eliminated, so it's a bit of a grey area in the electric/electronic definition.

And I agree that 'first to market' is a fair measure of firstness in this particular instance as ESA/Landeron were evidently playing with the Dynatron as a prototype for 5 years. Awards and chronometer certificates are all well and good but if it takes that long for a production-ready watch to emerge from a working prototype then where to you draw the line? Do you count the first public presentation of a design so long as it is eventually brought to market? That eliminates Omega and gives the point to ESA. But how similar really were those 'chronometer' test pieces to the mass market generic Dynatron that was released in 1967?

Stephen, perhaps you could make the 'first to market' claim explicit on your blog to avoid confusion. (Ah, I see you've got a link back to this thread; no worries then)


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## stromspeicher (May 28, 2015)

I normally don't like to stir up old threads, but I just found this one and I'd like to add something...

The best references on vintage Japanese watches are the so-called Japanese Watch Museum series of books. The relevant volume with information on the X8 watches states in the X8 product heading that the watch was released in March 1966. In the detailed text it then states -

"1966年（昭和41年）3月I0日 全国一斉に 発売されました"

This says that the watch was *released simultaneously across the country* on the 10th of March 1966. This doesn't sound like a limited showing of not-for-sale prototype examples - although Doensen apparently interprets it as such. Doensen actually doesn't mention this Cal 0801 in his book, just the later 0802 although they were certainly on sale and one or two a year do crop up for sale in Japan these days. I have seen enough examples of production watches with a *manufacture* date of December 1965 through to mid 1966 to support the 1966 release date. By 1967 Citizen were already selling the second iteration Cal 0802.

Citizen Japan also state in their online records that the X8 was released in March 1966, but are content to claim only that it was the first *Japanese* electronic balance wristwatch.

I don't know enough about the Dynotron history to draw any conclusions but on the X8, I personally take Doensen's offering with a pinch of salt.



stromspeicher said:


> The best references on vintage Japanese watches are the so-called Japanese Watch Museum series of books.


 ...actually the Japanese Watch Museum book is not what I meant... I meant the (Japanese) Domestic Watch series. (Apparently I'm not allowed to edit my post for some reason?)


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## stromspeicher (May 28, 2015)

....the other thing which might be interesting to add to this discussion is a note in a document about the history and development of Citizen watch company. The document is primarily concerned with the pre-war and immediate post-war developments, is reasonably well known and is written by Pierre-Yves Donzé. He says -

"After the war, it [Citizen] embarked on international expansion built on cooperation with foreign companies, including the American firm Bulova for the production of tuning fork watches (1960), the Swiss firm Méroz for watch jewels (1963), and the French firm Lip for electrical watches (1964)."


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