Yes, every JET has a supervisor. Some will be more helpful than others, though. Mine was very helpful on the day I first arrived in the prefecture. He picked me up at the Kansai airport, drove me 90 minutes to the town, showed me the apartment, police station, train station, post office, bank (where he helped me set up an account), and school, took me shopping for a few basic things, and took me out to dinner that night where he introduced me to the Vice Principal. But then he pretty much vanished until school started, leaving me to the VP (who was a great guy and spoke better English than my supervisor, but was busy with his own job). (I don't mean to downplay the help he gave me, it really helped get me started, but it was a whirlwind of activity, like "here's this, this, this, this, and this, ok, you're set, bye!" Or maybe it just seemed like that, having just come to Japan for the 1st time.)
He helped me learn some Japanese in the summer before school started, but after school I was pretty much on my own. I would get on my bike and just start riding, exploring the town, getting a feel for the place, etc. I found all kinds of places on my own, from other supermarkets to the video rental store to a wide variety of restaurants. Not having a car was a pain at times, but I got by... when I bought a nice stereo/cd system, the store clerks tied all of it to my bike (seat, handlebars, etc... with the boxes, it was pretty large) and I walked the bike home, 45 minutes, uphill, pushing the stereo-laden bike on a sweltering summer evening. But I got it home!
