Not likely to happen, as it would start a war. Wishful thinking though.
A long time ago when I used to be intrigued by the idea of a moon base. I even had a children's book called "The First Travel Guide To The Moon" which was set up like an actual tour guide to a non-existant lunar base.
Then reality hit, and I found out that both the US and USSR wanted to build bases on the moon but it was agreed that the moon would be "extranational territory" as it no nation could build a permanant structure there. This fueled by concern that a nation could effectively "conquer" earth's satellite for all intents and purposes, or use it to place missle bases aimed at the planet under the guise of a "research station" or whatever.
A lot of the things from science fiction that people could hypothetically do with a moon base have been thought of, and basically as long as the world remains divided into seperate nations it's not likely to happen.
I'd be surprised if Japan actually does anything besides talk about it, and perhaps plan it. There could be problems if they actually landed materials/robots there for real.
This is one of the reasons why I believe a world unity is nessicary for any serious space exploration. As long as the globe remains divided bickering over resources, and concerns over territory on things like the moon, or in the astroid belt, would render it impossible. Most concepts that deal with a divide globe somehow going about any kind of serious space exploration oftentimes gloss over key issues that would prevent it from ever happening.
I mean it's a neat idea and all, and I hope they develop the technology so it can be used when humanity is (hopefully) unified, but other than that it seems to me that they're jumping the gun in a big way.
Consider also that few people trust Japan despite the buisness they do. There are still hard feelings over that entire Imperialist thing which was less than a century ago, and nations like China and Korea might be diplomatic, but largely because the US has Japan under permanant occupation (even if we don't call it that) and we base mega-tons of our Navy there, it being one of our major pipelines into the Eastern World.
If Japan actually did it right now, it would basically be an American project for all intents and purposes (like it or not), we keep a close eye on their military/science/etc. This means that the USSR would likely get their panties all up in a bunch about it, as would China, and everyone else.
A sad truth is that one of the things that has held back space development (and again why I think like I do) is everyone being paranoid about what everyone else might put up there during "peaceful space research" as I said. Plus nobody is going to let you effectively stake out real estate on The Moon for fear of the precedent it could set.