Bringing in Camping Gear

Will immigration get suspicious or deny me entry if I bring in camping gear like a tent, knife, and sleeping bag as tourist? I plan on doing some camping during the trip at camp grounds and designated camp spots. Has anyone tried this before?

The knife might be the only issue on international flights.

I doubt very much if they will care as long as you have a hotel address for the first night. this is probably more common than you think. Of course as has already been said you would have to pack the knife.

Your own real problems may be if you gear has some soil/dirt on it and it's actually checked (quite rare). For your knife, just make sure it's put into checked baggage and others might know more about types of knives which may be illegal in Japan. I'm guessing these would be more like knives used most likely to stab someone....

Knife :
Remember basic Swords and Firearms Control Law.
http://www.police.pref.kochi.lg.jp/sections/seian/seikan/jyutouhou_kai...
https://nettv.gov-online.go.jp/prg/prg2418.html

Cassette cylinder, alcohol fuel :
Check the air company's rule first.
Because Japanese camping equipment has many imported items,
it would be better to buy dangerous items in Japan.

It would be faster to contact backpackers who have FB or blog and traveled Japan.
Because the forum users here usually only staying at hotel or ryokan.