Was in Japan in April (walking) but had a morning cycling around Osaka. Beautiful country and lovely people. It's expensive in the cities but OK out in the countryside. Found the food a bit odd but that's me, but there will be plenty of alternatives.
One thing if you've not been there before is the sheer amount of information in front of you. For example, in the rail stations there is a wall for detail in Japanese and English. The information you'll need is there but you just have to keep looking until you find it. You'll get plenty of help and if you transgress one of their many rules, someone will gently put you right so you don't 'lose face'
They've also a 'take your rubbish home with you' rule. Apparently something that is taught from a very early stage. Have a bag with you. An example.
https://www.bbc.co.uk/sport/football/63735823
Won't mention the communal (single sex) bathing. It'll be a surprise ....
You should get some tips in the 
