You're in the sushi capital of the world, but I would have to say one of the most popular sushi restaurants for middle class Japanese people is UMEGAOKA SUSHI-NO MIDORI SOHONTEN. (shortly called MIDORI SUSHI)
MIdori Sushi has several locations. Ginza, Akasaka, Shibuya, Daikanyama and 5 other locations, None of them take reservations and the wait could be as long 90 min especially Shibuya location.
I have a tips for the traveller who can't speak Japanese, choose the booth in stead of the bar, because you can make an order by ipad, have a picture of each items, so never missed .
If you own or manage Umegaoka Sushi No Midori Sohonten Shibuya, register now for free tools to enhance your listing, attract new reviews, and respond to reviewers.