Quote:
Originally Posted by
ChicagoRon 
One of my best foodie friends traveled extensively in Japan and told me this: There are a few places in the US that offer similar quality/creativity. What was most striking in Japan is how there are sushi restaurants that are very specialized, for example serving primarily one fish such as unagi or uni or tako in many different varieties...and that those places were the best he'd had for those individual pieces.
If you're at Tsukiji fish market, you'll get stalls that concentrate on one type of sushi only. What's more, they will sometimes only concentrate on one part of the fish - so a stall might sell only toro nigirizushi or sashimi (fatty part of bluefin tuna), or only maguro nigirizushi or sashimi (leaner part of tuna) and so on.
However, outside the fish market, most sushi or sashimi restaurants will serve a reasonable variety of sushi. I have been to one in Shinjuku that concentrated mainly on sushi made from various cuts of tuna, but it still served sushi made from other seafood.
It is definitely true that Japanese food restaurants in Japan tend to concentrate more upon a particular type of food or a particular ingredient, although usually not quite as narrowly as in the above example of the Tsukiji stalls. I've been to some fantastic places that simply serve kushikatsu (or food on skewers) or simply serve okonomiyaki or monjayaki (savoury pancakes). There are also restaurants that concentrate on grilled meat - they tend to serve primarily beef, but you can usually also get other types of meat there, too - restaurants that concentrate on particular types of noodles (ramen, for example), and restaurants that serve only eel-related dishes.