Living in a campervan in Japan

Is it possible to come to Japan from Europe, and buy a campervan to live in. So without a perminent adress?

How to get a visa is the first question. Then start asking more questions.

Millions of Foreigners will not agree to live permanently in campervan.so this is a stupid question.After spending millions of yen, inclu ding return airfare,we did not/wiill not visit japan to live in campervan whole time.Howev er 1000 yen per night hotel exists in japan.

Not a stupid question.

Millions of foreigners don't wanna visit Kagoshima. Does that make Kagoshima questions stupid also?

If the OP want to do their version of vanlife in Japan. It's their choice.

Regardless where you live you just have a resident status (aka “visa”) to LIVE in Japan. There are different options how to get a visa but unless you can get a dependent/spouse/child if Japanese Visa your visa is going to be bound to a work or a school. So a fixed place.

Also campervan sounds more expensive than living in a cheap rented flat or if you want to live in the countryside in a very cheap bought flat. But obviously only with a campervan you can move around.

I would be wary of the heat in summer though. It’s already hardly bearable in an apartment in the city but a campervan is a metal box…

You need an address. If that is where you are actually residing or not is a different issue, but it ties you to a city/municipality so they can send you things like your resident tax.
However, as others have commented, sounds like you haven't done anything about how to live legally in Japan yet. What work will you do? You can't just come and live here.

It depends on your definition of "live".

You can "stay" in Japan up to 90 days on a tourist visa, and you are free to spend your fortune on a camper and parking space during that time. Legal parking and camping is hardly free in Japan, but that doesn't mean you can't do it, again, as long as it's legal.