This Week’s Featured Watch #4 – The Monthly

Since four weeks equal one month, then maybe this one should be ‘Watch of the Month’ – and what could be better in that case than to feature the ‘Monthly’! Well I suppose it should be the ‘Monthlies’ since two such models feature in the Citizen vintage line-up, although they are quite distinct from each other in terms of their movements despite both being first produced in the mid-1960’s. Unusually these watches have a third window, displaying the month along with the conventional day and date windows. The month is manually selected via a second crown.

I’ll start with the slightly later model, which used the 5270 movement first produced in 1965, and is the version that is seen more often in the on-line auctions. Part of the Seven Star Deluxe range, this automatic movement was one of several lines using an oscillating weight system to drive them, as Citizen moved away from their circular geared ‘Jet’ rotor. The Monthly logo is found on models produced for the Japanese domestic market, whilst the export model became the ‘Moon-Dater’. Mine is from February 1969, and is a Monthly model:

The dial text says it all, with the Seven Star applied logo prominent above 6 o’clock. The case back also carries the Seven Star logo and the older style model designation of 4-52704Y, and the second crown to adjust the month, with its window in the chapter ring,  is at 2 o’clock. The case measures 39mm across and is the same lug to lug so it’s a decent size watch:

The 5270 movement, with 23 jewels in this model, beats at 18,000 per hour and can be manually wound but not hacked. Interestingly, the ‘Moon-Daters’ for the European market used the 21 jewel version. The date quick sets with the crown pulled out one click, the day is set by winding back and forth between 9 and 12:

Whilst the 5270 Monthly was an early example of Citizen’s use of the swinging weight rotor, their earlier model produced in 1964 was one of the last watches to use their ‘Jet’ rotor. I guess as a result it had only a short production run, and examples are rarely seen. As far as I can determine it was only made in gold plated versions, and mine is of the white gold variety:

As can be seen this Monthly is part of the ‘Seven’ autodater line, using the 19 jewel version of the 4101 movement. This time the month window is on the dial at the 9 o’clock position and is manually turned by the crown at 8 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 movement for its automatics.

Here it’s compared to 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:

So two Monthlies, but very different, and good examples of the incoming and outgoing movement technology of the day.

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12 Responses to This Week’s Featured Watch #4 – The Monthly

  1. Craig says:


    I have just picked up a black dialed monthly minus bracelet and with non-original crowns. May I trouble you for the lug width and crown diameters?

    Thank you

    • sweephand says:

      Hi Craig, I’m afraid due to family visit for New Year I can’t check the Monthly until Wednesday. I’m pretty sure the lug width is 18mm but will confirm that. If you need info urgently someone on the SCWF may be able to help in the meantime.

      • Craig says:


        Happy New Year and thankyou for the reply! Likewise I have family visiting so there is no hurry.

        By the way, I enjoy your Blog! It has got me interested in other than Seiko 😉 I am working on two 8060a Skeletons at the moment – both SS and Black versions.

        Thank you again.

    • sweephand says:

      Hi Craig – now had chance to check the measurements you’re after. Lug width is indeed 18mm, whilst the crowns’ diameter is a shade under 5mm. Hope that helps you find the right ones.

      Btw, have your 8060 movements got the rather nifty way of adjusting the time-keeping via the crown?


      • sweephand says:

        Hi Craig – for your info I’ve also seen domed crowns on these monthlies. Here’s an example in a ‘museum’ book, of a silver dialed version with split day and date windows:



      • Craig. says:

        Hi Stephen,

        Thanks for the info – much appreciated. You can find the 8060a skeletons if you look and pay the price! The 8060’s time can be set by pulling out the crown and turning. You can also manually wind by turning the crown in it’s normal position. I sourced an exploded view of the movement if you are interested – send me an email. The only trouble with them is their cases are small and the look puny on my wrist… but fascinating to see, hence my interest.

        The dial on my monthly has a few scratches (previous owner) so perhaps we can chat about that?

        • sweephand says:

          Hi Craig – I would like to look at the exploded view so will e-mail you about that, thanks. On the 8050 movements, used in the ‘Adorex’ specials, I understand that the crown can be pulled out to a third position and that can then be used to fine tune the timing, which of course saves having to remove the back to do it. It may only have been a feature of the 8050, which also had date and day windows.

  2. I just picked up a mint Seven Star Deluxe Monthly with a white dial in Kuala Lumpur. The marks on the back match your photo. I am wondering how to date it’s manufacture accurately?

    • sweephand says:

      Hi John, thanks for visiting my blog. Congratulations on finding a mint Monthly 🙂 These were made in the late 1960s, maybe 1970 too. The first three digits of the serial number give the date – first one is the year followed by the month, so if it’s, for example, 807xxxxx, then it was from July 1968.


  3. November ’68 it is. Thanks!

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