Review: G-Shock GA-2100-4A

I have this theory when it comes to watch collecting, and watch enthusiasm in general: no matter how focused your taste is in a particular type or genre of watch, part of you secretly wants to bust out and explore the polar opposite. I think this is a universal affliction of sorts. If you’re a vintage guy, every once in awhile you fantasize about going to a boutique and picking something up with the stickers still on, just once. Or, maybe you collect nothing but austere dress watches on fine leather straps. I bet that just once you’d like to own a tactical, sporty dive watch, walk around with it for a day or two, and just enjoy the fact that if you happened to be swept up by a tsunami at that very moment, even though you can’t swim, your watch would survive.

For me, this is the appeal of my bright red G-Shock GA-2100. See, when it comes to watches that I’m actually willing to throw down cold hard cash for, I tend more toward the conservative. Spare dials, classic designs, and diameters that wear easy. The contrarian watch I’ve always fantasized about? Well, it’s hard to admit this in watch nerd public, but an ultra modern (and ultra expensive) Royal Oak Offshore variant of some kind would be welcome on my wrist if one could be procured for me without the financial strain I’d feel if I, Zach Kazan, collector of the most modest means, walked into an AP boutique today.

What is it about the ROO? Well, for me, it has something to do with it’s unapologetic brashness as a statement watch. They get a lot of heat from enthusiasts because they rose to popularity with the endorsement of pop culture figures, athletes, rappers, and the like, representing something like a “real” Royal Oak but for less discerning, younger tastes.

But here’s the thing: I like rappers! And I like athletes and pop culture too, and I think it’s amazing and hysterical when I’m scrolling through Instagram and see Rick Ross wearing a white gold Royal Oak, or Pharrel wearing a Richard Mille, or whatever.


Review: G-Shock GA-2100-4A

Module 5611
Matte Red
Mineral Crystal
Resin Band
Water Resistance
200 Meters
48.5 x 45.4mm
Lug Width
Two Years

Enter, the G-Shock GA-2100. This watch can be had for $100 from a certain large online retailer. It has an octagonal case shape, not unlike a certain Holy Trinity brand’s famed sports watch, and it’s bright red. I mean, it’s really, really red. If you wear this watch out in a public place, someone is going to comment on the fact that it’s red. You’ll notice people’s eyes gazing at it awkwardly, probably assuming it’s a new smart watch, or maybe assuming that you’re Meek Mill. 

The GA-2100 has already been dubbed the “CasiOak” all over the watch internet, and other similar mashup nicknames are out there as well. But Casio has been making watches in loud colors in this general shape for years, so why does the GA-2100 suddenly seem to have claimed the mantle of Royal Oak on a hot dog budget? The answer, I think, is in how this watch wears, which is really unlike any other G-Shock I’ve strapped to my wrist. 

Basically, it’s thin. At just under 12mm thick, this is one of the most svelte G-Shocks Casio has ever made. While it would be an overstatement to say that it “disappears on the wrist” (which is the opposite of what you want this watch to do anyway) it’s incredibly comfortable to wear, something I’ve never thought of the many clumsily huge G-Shocks I’ve tried over the years. 

While this is a full featured G-Shock with timers, alarms, multiple time zones, and so forth, that, to me, isn’t what this watch is all about. This watch is about a look, a style. This is not a tactical watch and I’m not recommending it as a tool, I’m recommending it solely and exclusively as a design object. 

So let’s dig in to the design. 


Did I mention the case is red? It makes me think of the 1990s Chicago Bulls, or Clifford, the Big Red Dog. While Casio nostalgia raiding my brain might explain the appeal of this watch for me, I also want to talk about case’s dimensions, and how they’ve been slimmed down from typical G-Shocks to make the wearing experience completely different. 

This is a 45mm case at its widest point. Not a small watch by any means, but it’s also significantly smaller than many popular G-Shocks, which measure closer to 50mm and have unusual geometry that can make them a tough wear. The GA-2100, on the other hand, with its octagonal shape, is easy and comfortable to wear, even for long periods of time. The reason for this, I think, is that the top and bottom of the watch are significantly more narrow than the wide middle section. The watch feels small at the most sensitive parts of the wrist, but expands in its mid-section. It’s similar to wearing an oval watch, like a Patek Philippe Ellipse. Part of this is an illusion – the strap starts tapering almost immediately, making the horizon of the north and south poles of the GA-2100 disappear along with it. Still, that optical effect has a real impact on the wearing experience. It’s all about what you see when you look at your wrist. 

The case is surprisingly thin.

Also critical to the enjoyment of the case is a relatively new technology now making its way into G-Shocks of all kinds, the Carbon Core Guard. Basically, this is a thin layer of strong and light carbon fiber that reinforces the traditional resin case. The result is that G-Shock can build a case with a thinner layer of plastic material while still offering the same protection G-Shock is known for. If this case making technique is allowed to expand and trickle into other G-Shock lines (or create brand new ones) the possibilities are nearly endless. 

While not something you’d wear as a dress piece (unless you’re being willfully transgressive, which I’m on board for) the case has an undeniable ability to slide gracefully under a shirt cuff. There’s a novelty in this that long time G-Shock users will find endlessly amusing – to hold it in your hand is to understand it’s built to the same tough standards as every other G-Shock, but it’s light and thin enough to very nearly forget about.


The GA-2100 is technically an ana-digi display, but the little LCD window is so small and not terribly functional (more on that later) that the watch really presents and feels like a purely analog timepiece. A day of the week indicator near 9:00 is more legible than the small screen below it, but works more as proof of the module’s capability than anything else (this is a full perpetual calendar, after all).

So what we’re left with in terms of real world use on the dial is a pretty functional two-hander. The sword shaped hour and minute hands are the only components of the GA-2100 that are not red, thanks to some lume that could be stronger, so they stand out quite well. The twelve indices around the dial’s perimeter are in a slightly lighter shade than the dial’s base, and they’re raised, giving the dial a bit of depth and lending an extra touch of legibility.

Raised hour markers give the dial a nice depth

Every watch has a relationship between the dial and the case. The GA-2100 is interesting because the dial and case (and the strap) seem to all be part of the same object, as opposed to being distinct elements that make up a complete timepiece. Here is where the Royal Oak comparison actually makes the most sense – that’s a watch whose style is built on a harmony between the angular case and its integrated bracelet. But the so called CasiOak takes it a step further, blending not just the dial but it’s associated furniture into the same hunk of red plastic. 


The aforementioned LCD screen has an effective and quite enjoyable backlight, and when you turn it on, in the normal time telling mode, the watch’s wearer is greeted with a digital readout of the time as well as the seconds count. It’s also the home for using the various additional functions of the watch. There are a few problems here. First, the screen is just too small to coherently display all of the information you’d want to see if you were timing something, or checking another timezone. You can figure it out, sure, but it takes a second or two of additional analysis that just isn’t needed with a larger screen. The second, and larger problem, is that the screen is virtually impossible to read without the backlight, unless the dial happens to be completely bathed in direct sunlight. 

On paper, for most G-Shocks, this would be a fatal flaw. So much of the appeal of the standard G-Shock lies in all the stuff it can do. What we have here is functionally a time only G-Shock – I have almost zero interest in becoming more comfortable with the little screen. The surprise, though, is that I simply don’t care. Once again, this watch isn’t about the stuff it can do. It’s a G-Shock that’s purely about its own aesthetic appeal.

The digital readout is nice, but not terribly functional


Two factors contribute most significantly to the GA-2100’s wearability: the weight of the case, and the strap. 

The Carbon Core Guard’s impact really can’t be overstated. This case construction technique allows the GA-2100 to be made both lighter and stronger than many other G-Shocks, while still providing the hardcore tactical feel G-Shock users expect. The GA-2100 may be lighter and easier to wear, but it’s anything but delicate. 

The GA-2100’s slimmer case profile is matched by a strap that has been streamlined to match the rest of the watch’s proportions. This, in one sense, is a subtle difference, but changing up anything on a watch that has direct contact with your body will tend to have major consequences when it comes to real world wearability. While I wouldn’t claim that the strap itself is particularly comfortable compared to a nice leather strap, the fact that it’s quite a bit thinner than the standard plastic strap G-Shock uses makes it more wearable than other G-Shocks, comparatively speaking. 

On the wrist, the GA-2100 is light and comfortable


I’ll never be the type of person who’s interested in wearing a G-Shock on a daily basis. As undeniably cool as many of them are, at the end of the day, the thing that gets my heart pumping when it comes to watches is their mechanical nature. But that doesn’t mean I can’t have a lot of fun with a bright red G-Shock on a weekend afternoon, and that, I think, is what this watch is made for. For a collector, or anyone who looks down at a watch box with more than one or two choices in it each day, sometimes you just need a watch break you out of your comfort zone. The GA-2100 does that in spades, and at a price point where this small luxury won’t be painful.

The Carbon Core Guard allows the watch to be thin while still offering G-Shock level protection.

It should be noted here, that while my strong preference is for the bright red GA2100-4A, there are two other version of the watch floating around. One is totally blacked out (GA2100-1A1) and the other is black with white hour markers and hands (GA2100-1A). Tastes will obviously differ, but there’s something fun and vibrant about the red that doesn’t come through in the black.

As for the nature of the GA-2100 as a Royal Oak substitute: it’s definitely not. The Royal Oak is a classic and finely made Swiss timepiece, finished to a degree that has to be seen in the metal to fully comprehend. The GA-2100 is a plastic sports watch, with some features that are actually not too well executed. However, at least in red, it’s bold and brash carries with it at least some of the spirit of the early Royal Oaks, which were produced to, among other things, disrupt the watch industry. Nothing quite that important is happening here, but that doesn’t mean it isn’t a ton of fun. G-Shock

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Zach is a native of New Hampshire, and he has been interested in watches since the age of 13, when he walked into Macy’s and bought a gaudy, quartz, two-tone Citizen chronograph with his hard earned Bar Mitzvah money. It was lost in a move years ago, but he continues to hunt for a similar piece on eBay. Zach loves a wide variety of watches, but leans toward classic designs and proportions that have stood the test of time. He is currently obsessed with Grand Seiko.