Update of 48xx series movements

June 1977 – 48xxA updated to 48xxB


In our recently published article on A History of Grand Seiko – 1975 to 1988, we discussed how between volume 1 and volume 2 of the Seiko 1977 catalogue, the entire range of Seiko Grand Quartz was updated.

Before writing the article, despite having a pair of Grand Quartz 4843-8050 and 4843-8100 watches in our private collection, we hadn’t actually noticed this wholesale change as we’d not performed any thorough research into the catalogue contents. It was only by examining the case-backs of those two references that we spotted a material difference between the two.

4843-8050/8100 comparison

The earlier 4843-8050 watch is on the left, and as can be clearly seen from the photo, it has a larger battery hatch, and a deeper case back.

This prompted us to look at an old binder of Seiko technical manuals that we had on the shelf, and discovered the reason for the change – there are two different 4843 movements, 4843A, and 4843B.

It was clear, without even having to remove the case-backs to check the movement numbers, that the earlier 4843-8050 reference was using the 4843A movement, and the later 4843-8100 the 4843B movement with its smaller battery.

Our research into the top-end Seiko quartz ranges of the 1970’s also included cataloguing all of the Seiko Quartz Superior references, and we will be publishing an in-depth article on the Superiors towards the end of this month, or early next. That research uncovered a very similar change to the 4883 Superior movement, in that at the same time the Grand Quartz moved from the 4843A to 4843B movement, the 4883-8000 Superior was replaced by the 4883-8100 – presumably the Superior movement architecture was also updated to take advantage of the new battery technology.

Seiko Watch News – June 1977

Following the publication of our article, Anthony Kable of Plus9Time reached out to us to share an issue of Seiko Watch News from June 1977 that he had unearthed in his archives.

Anthony had discovered that this issue of Seiko Watch News detailed the change that we had identified during the research for our article on the Seiko Grand Quartz.

The date of the newsletter is key, because of course it would have been issued right before the publication of the second volume of the 1977 catalogue that, whilst containing details on all the new references, failed to mention the reason for the changes.

Above photos and details of a selection of updated references from both Grand and King Quartz ranges, even without translating the Japanese we can see that it being communicated is that 4883A (Superior), 4842A and 4843A (Grand Quartz), and 4822A and 4823A (King Quartz) movements are being replaced by their “B” counterparts.

Using Google Translate, we are able to get a fairly good approximation of the text at the top of the page, that we present here –

“Specifications of 48 series quartz are partially changed.

Seiko Quartz Superior (4883)

48 Grand Quartz

48 King Quartz

For June production, some specifications will be changed as follows:

1. Conventionally, we used the UCC-301 battery, but from June production, we will change to the small, thin, SB-A4 battery.

2. As a result, there is no protrusion of the battery hatch at 12 o’clock on the watch case-back.

3. Due to the change of batteries used, parts of the movement have also been changed, so we are introducing a new caliber.

Superior – 4883A to 4883B

48 Grand Quartz – 4842A to 4842B, 4843A to 4843B

48 King Quartz – 4822A to 4822B, 4843A to 4843B

There are no other changes in function or performance.”


We will be updating our article on the Grand Quartz range to include this additional information.

We would like to take this opportunity to thank Anthony for his research into this change, and for providing a scan of the relevant issue of Seiko Watch News. If you haven’t checked out Anthony’s site before, we very much encourage you to do so. Anthony is one of the world’s foremost scholars on Seiko history, and his generosity in sharing the fruits of his experience and vast knowledge is something that we have benefited from countless times in the past.

You can also follow Anthony on Instagram here, where he shares what is seemingly an almost unending supply of Seiko references, collectibles, and ephemera from his vast collection.

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