Kaiten-Zushi: Conveyor Belt Sushi
Rice and Raw Fish on the Cheap
The cheapest and most popular form of sushi restaurant is the kaiten sushi (actually the name is kaiten-zushi, with a “z”, but since most people use the term “sushi” we'll stick with that here). In kaiten sushi restaurants, a conveyor belt carries various plates, each containing one or two pieces of sushi, around the room, passing by each table at least once in the process. If you see a dish pass by that looks particularly enticing (a nice pair of fatty salmon nigiri for instance), just pull the plate off the line and eat. When your sushi dining experience comes to a close, you press a call button and your server tallys up the number of plates (most are color or size coded for different prices) and you receive your bill.
In the larger, chain restaurant versions of conveyor belt sushi, you are able to place special sushi orders via a combo touch screen intercom system at your table. Some even have games for kids. At Kura Zushi (my wife's preferred sushi restaurant), you drop your used plates into a slot at the end of your table. Once you drop five plates, a little animated game pops up on the touch screen ordering system. If you win, a small prize pops out of another slot up top, usually something like a charm to hang on your cell phone or a small child's toy. Kura Zushi is very popular with kids and big families for this reason.
Of course there are rules that go along with this type of sushi restaurant. First and foremost, if you pull a plate off the line, it's yours. Decide that you don't actually want that matching set of natto wangun sushi? Fine, but don't you dare put it back. Nobody will force you to eat it, but you will have to eat the ¥100 that that plate of sushi costs.
Keep an eye on your kids (assuming that you're so equipped) and make sure that they don't do anything unsanitary near the food. This is one of the advantages of living in Japan. Any restaurant that has the general public seated a foot away from sushi meant for human consumption is not likely to be popular in the US. There would always be some jackass (or several) not following protocol. In Japan however, you can bet that 99% of the general public will be following the rules and will fully expect others to do the same.
P.S. I have actually seen a kaiten sushi restaurant or two in the states, but in both cases the sushi was fully encased within a plastic bubble while on the belt. This obviously creates more trash, but at the same time it gives people less room to make "mistakes".
2011 UPDATE: Kura Zushi is now doing the "sushi in a plastic bubble" thing at many of it's restaurants. Personally, i am not a fan of this style so we have switched to Sushi-Ro.
Recently (2011) Kura Zushi's competitor, Sushi-Ro has updated the system in many of their restaurants. They now feature larger and higher tech LCD screens than those used at Kura Zushi, with the ability to click a button and see what you have ordered, what has been delivered to you and what part of your order is pending.