There are sushi conveyor belt places around - one popular place in in the middle of Omotesando and always busy. There is even one on floor 5 of NRT term 1.

Lately, there has been a revolution in sushi - some smart guys have figured out how to get around the monopolistic wholesale system and founded their own chain of restaurants with a vertical fish supply chain. This has resulted in low price and good quality.

One of the more famous is Sushi Zanmai, has locations around Tokyo http://www.kiyomura.co.jp/sushi-e/

A great sushi experience is to go to Tsukiji market in the morning and then top it off with a breakfast of sushi. There are many restaurants around the market, only a few are famous. Try Sushi Dai:

ttchu.com/Food-Dining/Food-Dining/Sushi-Dai-…

siuyee.com/2005/09/26/tsukiji-fish-market/

As yamanote-san mentions, try this one: kiyomura.co.jp/sushi-e/shop/shop18_01.html

It's convenient and cheap. The fish here is pretty good quality.

In general, it's best to avoid conveyor belt sushi. The stuff is not fresh and the quality is low.

Kaiten sushi, while lower in class can be fresh and pretty decent quality in Japan. The place I mentioned falls into this category. Handmade and called to order is a strategy that should be used at these places. You can also watch the chefs to see what is fresh as they put it out.

Route san is right. Kaitensushi in Japan is 100% different from US kaitensushi. A good kaitensushiya does not have any sushi already made on the conveyer belt. The only things they have on it will be wasabi and gari, etc.

I highly recommend Sushi Daidokoroya on Dogenzaka in Shibuya. Very good and cheap!!

My favorite place is Midori Sushi at Ginza at a street called Korida-dori, between Shimbashi and Yūrakuchō stations. For 2,100 Yen, the sushi set itself is already excellent. It is also served with a salad, chawanmushi (steamed egg), and miso soup. Note that Midori has a shop at Shibuya as well but it is not as good.

http://www.bento.com/rev/1534.html