Hi...nice to have you onboard the RC aircraft site.
f you are really interested in jets you may want to start by asking some questions in the "Jet" forum.
I feel you will get many more good and helpful answers from the people in that forum as it is all about jets.
I wish you all the luck in the world with your new hobby. You will be amazed at what these "toy" jets can really do. Be prepard to spend lots of money on the jet end of the spectrum.....and then be prepard to have lots of fun.
Here in the U.S. one does not just buy the parts for a true jet powered model and go fly it. You need to be checked out and signed off by someone else that has many hours in these jets before you can just go flying them on your own.

I'm sure in time you will find some very good jet pilots in Japan that will help you as well.
That's all I can help you with so have a great time and be carful