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SOLD - Grand Seiko 4520-8000

Cap gold case

A brief history

The 45GS series was Daini-Seikosha’s second for Grand Seiko, taking over from their seminal 44GS whose final catalogue appearance was in the second volume of the 1968 Seiko Catalogue.

Launching in the supplement to that publication, the 45GS references retained many of the “Grammar of Design” elements that the Grand Seiko 4420-9000 is so famous for introducing, but there were far more significant changes “under the hood”.

A year prior to the introduction of the 45GS, Daini had tremendous success at the final “Le Concours chronométrique de l`Observatoire de Neuchâtel”, with watches submitted by them taking 4th, 5th, 7th and 8th positions in the top 10.

I was very fortunate a few years ago to be able to add the watch that took 7th place to my collection. “052561” (its movement number) has a published “N-score” number of 2.12, but on checking the maths I found three errors that were made on the original bulletin, and the correct N-score for the movement is actually 2.10, which would have bumped it up to 5th place, making the second best performing Seiko movement of all time at the Neuchatel trials!

Here’s a photo of the watch from a visit I made to the Neuchatel Observatory in 2019 -

Of course, the most significant difference between the 4420A movement found in the 44GS, and the 4520 movement that resides in the watch offered for sale, is that the 45GS references are powered by watches whose balance oscillates at 5Hz, resulting in 36,000 bph - as proudly declared on the dial, twice the beat rate of the 4420A movement.

Clearly many of the lessons Daini learned from their participation in the Observatory trials were applied to the design of the 4520A and 4522A (with date) calibers. So good in fact are these movements that the 4520A was chosen as the movement to be used in Seiko’s legendary Astronomical Observatory Chronometers, with the initial batch of 103 movements being submitted to Neuchatel for full Observatory Chronometer testing in late 1968, of which 73 passed, and were cased into watches in June of 1969.

Here is a photo of one of those movements. Note how the movement number is engraved not just on the bridge for the going train, but also on the baseplate of the movement under the balance.

One of the little appreciated facts regarding the 4520A movements in the first batch of the Astronomical Observatory Chronometer is that the very best of them outperformed the Grand Seiko VFA standard by very nearly a factor of ten. Yes - that’s right. A factor of ten.

Which makes them as precise as the first Seiko Quartz Astron.

But I’m not offering an Astronomical Observatory Chronometer for sale. Well, not today at least, so let’s get back to the 4520-8000 in cap gold…

As can be seen from the catalogue scan above, the cap gold variant of the 452x-8000 sold at an 8,000 Yen premium over the stainless steel cased one - which in the instance of the 4520-8000 works out to be 30%. This may initially sound to be very high, until you consider the fact that the gold cap is 300 microns thick - which is a surprising amount of gold!

The reference remained in the catalogues all the way through until 1972 and clearly was very successful, as it is not a particularly difficult watch to acquire even 50 years after it was retired from the range.

Having said that though, the number of examples that have survived those 50+ years in the condition of the watch offered for sale here is very, very, small indeed.

Condition and price


It is a simple fact that the 14K gold cap found on this watch is significantly softer than the stainless steel cased variant.

This, combined with the fact that people generally like to keep their gold watches clean and shiny, means that the vast majority of vintage Grand Seikos with cap gold cases that we see on the market today have cases that often show both significant dings and scratches, and have been polished in attempts to minimize those very blemishes, which sadly significantly softens the caselines. A good example of how these cases all to often end up can be seen in my recently listed 6246-9001 in cap gold.

No such worries here, in what without question I would categorize as a “99th percentile” watch, and one whose case I am all but certain has never been polished - just take a look at this screengrab from the video -

You will not come across a sharper cap gold case than this one, and I do encourage you to spend plenty of time admiring it in the video, because only one collector will get the chance to admire it in the metal!

One obvious thing regarding the case is that it does show quite a bit of tarnishing, which is only to be expected for a cap gold case that has (almost certainly) never been polished. I did umm and ahh about whether to attempt to remove the tarnishing with some jewelry cleaner (I have had success with this in the past on other tarnished cap gold cases), but quite honestly I personally much prefer it untouched, and would recommend to the collector who purchases this watch to not give into temptation and subject it to a spring clean!


As will also be evident in the video, the dial is just about as good as you could ever hope to find on a vintage Grand Seiko, with just a very small spot about a quarter of the way out from the center of the dial in the direction of the 4 o’clock index, and a tiny tiny one between the indices at 5 and 6. The former probably wouldn’t even register to the naked eye unless it was pointed out, and the latter is imperceptible.

I’ve added in some dial detail movements at the start of the video, and you will notice that there is not even the slightest hint of any dial degradation at the periphery.


Once a purchase is confirmed, the watch will be sent to my watchmaker here in Thailand for a movement service (the case will remain untouched) including a full stripdown, clean, rebuild, lubrication, and regulation. The movement is then guaranteed for 12 months subject to the usual abuse/water damage exceptions.


The price for the watch, including fully insured worldwide courier delivery by FedEx, the pre-shipment movement service and 12 month guarantee, is US $2,800.

As usual, this newsletter will be first sent out to paid subscribers, who can take 10% off that amount should they place an order in the first 7 days following publication (bringing the price to $2,520). Following that one week exclusive period, should the watch remain unsold, it will then be additionally offered to free subscribers, and the 10% discount will no longer apply.

Should you have any questions regarding the watch, please do not hesitate to contact me by replying to this newsletter if you are reading it in an email, or by emailing me direct at the usual address (contact at thegrandseikoguy dot com).

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The Grand Seiko Guy