There is a certain art to making sushi. For a lot of people it is the definitive in Japanese cuisine yet there are a lot of misconceptions about it, which is strange for something so minimalist.
The word sushi is a shortened way of saying its full name "sushi-meshi". The words actually mean "vinegared rice" and refer to about 30 different varieties all using the same rice base. The rice used is almost exclusively the Japonica variety, as long grain and short grain types which although are common have unfavourable qualities in terms of stickyness.
What you'll usually find in most sushi stores and for quick take-away are limited to pnly 3 basic types:
Inari - which are a hand pressed block with the neta (topping for want of a better word) draped over the top, these may be tied with seaweed (nori) if so desired.
Futomaki - These are the classic large rolls with the nori on the outside. Typical futomaki are two or three centimeters thick and four or five centimeters wide. They are often made with two or three fillings, chosen for their complementary taste and color. Increasingly in a faster paced society they are left uncut and can be as long as 15 centimeters long.
Temaki - A large cone-shaped trumpet (rather like the Belgian method of serving take-away chips except that they're smaller and you can eat the wrapping), with the nori on the outside and the ingredients spilling out the wide end. A typical temaki is about ten centimeters long, and is eaten with the fingers since it is too awkward to pick up with chopsticks.
I'm nopt entirely sure why but a lot of people immediately associate raw fish as being sushi. This is interesting as the Japanese word for fish is sakaki and the method of thinly slicing it is called sashimi.
Even more strange is that sushi is seen as an exotic food, whilst the ingredients and the equipment aren't common in Western homes, in Japan they are almost de riguer. A sushi in Japan would be as common as a meat pie in Australia, a burger in the US and a lamb roll in India. You can pick up a quick snack at most railways stations and Quick-Stops for about ¥100.
Really if you wanted a quick example of what a region's cuisine would be like then a bento (wooden lunch-box) would be a good way to go.