In past decades Japanese companies made a lot more models for just its own market. Aside from some items that use something specific in Japan (like radios that cover Japan's idiosyncratic FM spectrum) , today for items like cameras models are generally made for a world market - so you'd actually find it very hard to find a camera that wouldn't have an English menu.
More importantly though is the item price and features that you are looking for. If you are coming from Australia or the EU for example, you'll probably find Japanese prices appealing. But if from the US you'll probably find the same item cheaper where you are and not in Japan.
There are some other good reasons to buy the camera before you get to Japan. The first is that learning to use a camera on the fly is not the best way to do things - and you will have a higher probability of taking bad pictures as you learn how to use the camera while you go along. If you get used to the camera before your trip, you will have less frustration and not waste time.
Another reason is that if you buy the camera in Japan and there is a problem, the warranty is likely only valid in Japan. There are international models, but those are generally more expensive.
One suggestion I would give is that you not only consider photos, but also take some good video as well. To capture the sights and sounds of an area can be so much better than just a snapshot. For better future proofing, you might want a camera that takes 4K video for stunning clarity. You'll need the appropriate SD memory card also (the UHS 3 type).