Seiko claimed numerous world firsts throughout their years, from (arguably) the first automatic chronograph, the first commercial quartz watch (which, at the time, was way more expensive than mechanical ones), and they also were the first to launch a proper analogue chronograph watch that happened to be quartz – the 7A28.

There were a number of variants in case style, but the most sought-after of the 7A28 is the military-issued one known as the RAF Gen 1 (and an RAF Gen 2 came along later using a different movement). To give it the correct name, it’s a Seiko 7A28-7120.

The first 7A28s appeared in 1983 and their successor, the 7A38 – which featured a date and day display on the 3’oclock subdial – showed up a year later, yet the mil-spec model that was made for the RAF was first issued in 1984 and continued unmodified until 1990. In total there were just over 11,000 produced and stamped with MoD numbers.

The most obvious differences between these watches and the consumer 7A28 is that they have fixed bars on the case (rather than spring bars) – a common standard on military watches – as well as a circled P mark on the dial and some other insignia on the rear. Otherwise, it operates exactly like the 7a28 or 7a38s that are available in lots of other case styles.

See the video at the bottom of Chris’ podcast interview with me, talking about Seikos and showing the 7a38 doing its thing.

The NATO Strap that’s normally worn with these got its name from the NSN or NATO Stock Number that’s stamped on the back of military-issued equipment – in the case of the Seiko, here, the NSN is 6645-99 7683056, which decodes as

6645 = Time Measuring Instruments

99 = United Kingdom

768-3056 = individual part number


Below the NSN and the “Broad Arrow” mark (actually called the Admiralty Arrow, and historically stamped on any number of things indicating they were property of the Crown) is the issue number and the year it went out, and below that is the actual Seiko serial number. So the watch above was given to some service person in the RAF in 1990, and by decoding the Seiko serial I know it was made in January 1990. Gulf War era then.


I bought two of these from an auctioneer who was disposing of all kinds of military surplus stuff; both were a bit beaten up and not working, so off they went to my Seiko specialist and came back in great shape with new crystals and having had a full strip down and re-assembly.


Quartz watches got really cheap in the 1980s, and had a reputation of being disposable – lots of fragile plastic bits inside, and no reason to try to service them. If you own a high-end watch with a quartz movement today, and you send it to the manufacturer for a service, it’s standard practice just to replace the whole movement.

Not Seiko, though. This was a proper movement that could be stripped, cleaned, oiled and reassembled just like a mechanical one.



Note the P on the dial – military specifications dictate that they needed to carry this mark as there is a trace of mildly-radioactive Promethium in the luminescent material on the dial. The same circled P is on the Seiko RAF Gen 2 as well.


So, fully rebuilt and on a raw leather NATO, it makes a great tool watch. And it probably saw a much harder life in the hands of its first wearer than it ever will with me.

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By ewand

14 thought on “Seiko “RAF Gen 1””
  1. Would you care to divulge your specialist Seiko repairer? I have 7A28-7120 Serial No 10024/90 which I have used for since the early nineties when I purchased it from an ex military watch dealer. It does need some TLC and I would like it restored by someone who knows what they are doing. I would be grateful for your recommendation.

    1. My specialist is a hobbyist rather than a professional (at least for now) so I’d recommend going to SCWF ( and asking for references based on where you live.

  2. Great looking watch, would love to know who your specialist is as I have one that I would like to be repaired to the same standard

  3. Is there any way of deciphering whether it would have been issued to the RAF or Royal Navy from the issue number/year?

    1. I don’t think so, Richard – I’m not even certain that the Gen 1 was issued to any navy pilots; the Gen 2 that followed had a non-luminous version that was giving to submarine crews but if naval aviators got any of them, I suppose they came from the same supply chain as the RAF.

      1. I was issued with a Gen 1 at HMS Osprey, RNAS Portland in 1984. It was a fantastic watch which I wore daily until I left the Navy in 1996. Really regret not having “lost” it and paid the fee for losing it on the famous form S126 which the Navy used to write off lost or destroyed items to recover their book value from the careless permanent loan holder – ie the navy pilot in this case.

        1. What a great story, Colin! Don’t suppose you know what the serial number was, do you? These things have a habit of turning up again…

  4. My Seiko Gen 1 has always been in MoD hands in one way or other although its individual history is unknown. It was passed to me by a colleague. It then had no strap and was not working, probably due to the need for a replacement battery.
    I already owned a A728 7020 from new in the late 1980s. This had a hard life as my personal watch used daily. The mineral glass was chipped and finally ‘frosted’ all over during a climbing session in Cornwall. After a year or so in a drawer I sent it to Seiko UK. A full service then costed just over £110.
    An A728 7020 can be seen briefly on Roger Moore’s wrist in The Spy Who Loved Me film. It is sometimes known as the James Bond A728 making it one of the very desirable versions.
    I’d strongly recommend using the Seiko UK repair service, not cheap but excellent. Rumour has it they use the finest of batteries that last for an incredibly long while. The Gen 1 full service inc. new tiny gaskets on all the buttons and a new mineral glass costed around £130 about four years ago.

  5. My 1988 7A28 is in need of another service and battery, last time I sent it to the Seiko service centre but today they have told me that Seiko no longer manufactures the parts, so cannot help me; hence my arrival here!
    A friend of mine was a Tornado jockey and still has his, he says the RAF is the only company which makes you pay for your watch when you retire!

    1. If it’s not too late for you, check out the Seiko Citizen Watch Forum (SCWF) – there are plenty of people on there who could service it for you if required.

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