‘There’s something appealing about your watch not knowing everything about you’: My 10 days in Japan with a Casio’s ‘dumbwatch’ MUDMASTER

It might just be a millennial thing, but I’ve been fascinated by Japan ever since I was a child. Japanese culture was huge in the 90s, and my brothers and I soaked it all, from movies and manga to video games and beyond.

Even though my love for the country never subsided, I had to wait until 2026 to actually make it to the land of the rising sun. I spent a week and a half in Tokyo, and it was an amazing experience, despite the heat and the humidity (and the constant threat of earthquakes, hurricanes, and other natural disasters).

As I was getting ready for my life-changing journey to the east, I had to make some decisions on what to take with me. Naturally, I packed my Fujifilm camera and a vlogging device, as well as minimal amounts of clothes (I assumed I’d be doing some apparel shopping, rightly so).

The wearable dilemma

One of the gadgets I contemplated the most was wearables. I have dozens of smartwatches and smart rings at home, each more advanced than the other. They can all track sleep, exercise and stress, on top of more obscure health and fitness metrics. In fact, they can monitor so much that the data provided sometimes feels overwhelming.

This might explain why I opted to only take my Oura Ring 5 and my Casio MUDMASTER GG-B100XM-1A. Why on earth would I take a dumbwatch to Tokyo, knowing that I’ll be doing 20,000+ steps a day? How about tracking how my body is coping with jet lag?

I considered all of these before setting off. Sure, the MUDMASTER isn’t a wearable you would necessarily pick as a daily tracker. Even Casio has a somewhat better non-smart watch option, the G-Shock DW-H5600, which is a lot less bulky. Yet, when I was looking at my options, I decided to take the MUDMASTER with me, anyway.

Big watch energy

My main reason to take this particular watch was that it looks great. Sure, it’s a MUDMASTER, and therefore it’s bulky and rugged, but boy-oh-boy, doesn’t the GG-B100XM-1A look great? Everything from the bio-based carbon case and stainless steel bezel to the protruding buttons and mineral glass lens work together perfectly.

There is something enduring about the design of the watch. It looks sophisticated but also tough, old-school yet modern. While most people on the metro were staring at their smartphones (or nodding off), I often found myself playing around with my MUDMASTER, pressing the buttons so the light comes on, or checking different stats.

Yes, the GG-B100XM-1A isn’t a true ‘dumbwatch’ – it actually has a few sensors and tracks a few basic stats, like steps, altitude, air pressure, and so on. It even connects to your smartphone, although its connectivity prowess is far from full-blown smartwatches. Still, it does track a few things, which is more than enough if you’re on holiday.

When the heat is on

One of these metrics is temperature, which I kept a close eye on while in Tokyo. During the time I was in the megalopolis – late July – there was more than one kokushobi or “cruelly-hot” day, as temperatures rose above 40ºC.

I often ventured outside in the early morning, spending time walking around before the sun really powered up, then retreated into my apartment just before the hottest part of the day. Then, when the temperatures dropped, I went out again to see Tokyo in its full neon glory.

The GG-B100XM-1A’s heat sensor was a bit of help. I tried not relying on my smartphone continuously to conserve data, so having my watch tell me how hot it was helped a lot. Of course, I could feel the humidity and heat without the MUDMASTER telling me it was toasty, but something about numerically confirming this put my mind at ease.

No training, no problem

Another reason why I chose the Casio was that I wasn’t training while in Tokyo. It’s not like I didn’t want to; I saw many people running. I even managed to get in a couple of bodyweight workouts in my air-conditioned hotel room.

But due to my sciatica injury, I wasn’t able to run, and even walking around caused a considerable amount of pain. Running simply felt too much. If I were to train, I probably would have picked a Garmin watch instead of the MUDMASTER. But alas, it was not meant to be!

To be honest, looking at those runners doing their laps around the Imperial Castle in the morning, when it was already 28ºC and humid, soaked in sweat, I think I might have dodged a bullet by not even trying to exercise outdoors. Walking in that heat was enough.

(Luckily, I discovered a shiatsu massage place in Ginza, and it eased my nerve pain a lot. But that’s a different story altogether.)

A homecoming of sorts

My final, and somewhat sentimental, reason why I picked the Casio was to take the watch back home. Casio’s head office is actually located in Tokyo, and even though I haven’t visited it, taking the MUDMASTER with me felt like the right thing to do.

Yes, I know, it’s a bit cheesy to take a Japanese watch with me to Tokyo, but I didn’t care. Did wearing the GG-B100XM-1A over the, let’s say, Samsung Galaxy Watch Ultra 2 feel like a better choice? Well, it did for me, and that’s the main thing.

Over the 10-day period, the watch really grew on me, so much so that I might end up wearing it when I’m not testing smartwatches. There is something about your watch not knowing everything about you that makes it a more appealing option.

The MUDMASTER GG-B100XM-1A is available to buy now at Casio UK and Casio US in a number of colourways for the recommended price of £369 / $440.