This place rocks my socks as far as good, cheap Japanese food goes. It may not appear like much from the dirty building, but its worth a visit. I am going there in a few minutes for lunch, actually. What I like about it is the "genuine" feeling you get, that it isn't some knock-off, wanna-be place.
I generally get the sandwiches, that have "tonkatsu" (fried pork) on THICK white bread (with the crust sliced off!) and 2 huge lettuce leaves with mustard/mayo. Very yummy and definitley different. Other wonders include "hamburg" which is a hamburger patty with radish stuff on top, served with rice and a side of pasta. They do have other things besides the breaded meat, like lemon pepper chicken that is "healthy" and some pasta-like dishes.
Its a quirky but quintessental international district place. But don't tell anyone, its already kinda busy at lunch.