Casio G-Shock WW-5100C-1

Casio G-Shock WW-5100C-1

Here’s an early G-Shock that’s getting harder to find — the WW-5100C-1.

It’s identical to its rarer sibling, the WW-5100C-9, using the wide-temperature 491 module, but has subtle styling differences. The -1 has a grey and white colour scheme, while the -9 is the gold version.

I managed to pick this one up locally which was a bit of a bonus; here in NZ we didn’t get the large numbers of stock as the more lucrative markets of North America and Asia, but it also means there aren’t as many collectors down here so when nice pieces like this come up for sale, there is a bit less competition for them.

The 491 module is kind of indestructible which is nice (although a light would have been a handy addition; at least without a light you know you have a real 491, and not a 240) and it’s just a nice looking watch generally.

Production numbers are estimated at 5000 for this watch (and the -9) which makes the serial number of 010966 particularly interesting. The -9 I owned had the serial 512731 which makes me think they didn’t start at 000001. So possibly (and this is pure speculation) the first two numbers could be a batch number and the last four the actual serial which would make the -1 among the first thousand produced. Wishful thinking I know, but you never know. Low serial numbers of any watch (i.e. those starting with a 0, are greatly intriguing).

So a rare watch, and rightly so. The 5100 was the second G-Shock produced and, had it not been for the 5200 reviving the brand, it may have been one of only three models which would have made it as scarce as rocking horse poo. As it is, a classic and appealing watch that always attracts interested comments (and some drooling from collectors) 😉

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13 Responses to Casio G-Shock WW-5100C-1

  1. Howdy from Australia, Did you know Farmers in Auckland sold the ww-5100-9 back in the 80’s I bought one as a divers watch, still have it today but not the orginal bezel sadly but a copy fro Brazil, but wear it every day, still works like new. Serial number is 512906.

    • Hi Greg – thanks for the heads-up! That would explain why a few have surfaced in NZ over the past few years. It’s interesting that Farmers (a Kiwi department store) got a swag of these to sell, particularly since they weren’t produced in large numbers to begin with. You did well to score one then – although at the time it would have been surrounded by all the other cool Casios from that era so maybe just a fraction less exciting than if you found one on the shelf today. Great you still have it as a daily wearer too, your mates probably just see a watch — not a $1-2K investment! The Brazillian bezels aren’t a bad replacement at all (although I wish they would sort the font thickness to make them look more like the originals). Hopefully the next generation of 3D printers will mean we can make our own replacement parts to a more exact spec, than having to rely on a single injection-mould.

  2. Hi,
    so glad I found your comments about the G-Shock.
    I have one that I have since 1985, model WW-5100. Ser no 509601, bought in South Africa. My younger brother bought it originally, and I thought the seven year battery life to be a good fable. How wrong I was!
    The local SA agent says spares are discontinued and thus not available, but I see you mention a Brazillian bezzel.
    Where can I get hold of a bezzel and strap, and approx price if available.
    Or else, will any other model have a compatible strap/bezel?
    The 3D printing seems a good idea.

    • Great that you still have a working WW-5100. Contact an eBay user called and see if he has the after-market bezels available. You should still be able to find an original band as these still popup regularly on eBay.

    • I’ve never heard a definitive answer on this — some uncredited source says it’s to do with how they make the LCD, but having had a few of these modules apart I can’t really go along with that, since the amount of space etc inside it is the same as a normal module. My guess is it’s either to confirm it’s a genuine 491 module, not a 240 that’s been substituted, or that while the LCD was specially made to withstand extreme temperatures the same could not be said for the lightbulb that may have failed at either very cold or very hot temps.

      • thanks. well let’s keep the mistery then. I think it wasn’t very clever move.

        Still I was interested by this watch, albeit the screwback (they didnt work well for me, move around too much on my “variable-size” wrist) because it is the only square with a “special feature”. And the crystal looks quite good..until i discovered it is the most expensive square around… 🙁 i will pass.

        drooling auction : 🙂

  3. I have a Casio (491)WW-5100 that I purchased new in 1983 from Macys in San Francisco Ser.# 005051. Can anyone tell if is a real 5100. I’ve never seen one that the ser.# started with 00. Any help would be appreciated

  4. I just picked up a WW-5100 at a tag sale. It’s just the head minus the case and band. I am trying to sort the serial number issue. Mine starts 010XXX. Are these number random or do they have a meaning?

  5. I inherited my father’s ww-5100. Serial number 000794. I’m trying to find a replacement bezel as the original fell apart.

    • Original replacements haven’t been made for around 10 years now. But there are good aftermarket replacements available – check eBay for these.

  6. Hello; I bought mine this year (2023)… was a long journey to find a good WW-5100 to my collection. My WW-5100 had a serial starting with 003. I think that this number are random and do not have a logical sequence. Cheers!

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