This is the best and most authentic Japanese food in AZ. Toh Zan serves up the tastiest original Japanese food that I've ever tasted, even in comparison to LA's Japantown. The restaurant is a bit small and the owner might seems standoff-ish but they are polite and nice people.
I don't like to be waited on hands on foot so this actually fits my lifestyle.
In the summer months, you should try their cold noodle, especially Ten Zaru (cold noodle with shrimp & veggies tempura). My wife really like their Chicken Katsudon. The meals generally comes with some sides (salad, miso soup, etc) and in generous portion. The food is never oily and taste fresh.
Give this place a try and you will not be dissapointed.