Ozumo's modest front entrance leads into a very large, buzzing restaurant. There is an initial bar area, then an open kitchen with a counter and some secluded tables, and then a further, airier section with another large open kitchen with counter seating and plenty of additional tables. The whole place seats well over 200 diners, and even at an early weekday lunch it was packed. A wide selection of sake is available.
I had the tonkatsu bento box. The tonkatsu itself was fine, slices of breaded pork (as distinct from the traditional whole deep fried cutlet) perhaps a touch drier than ideal but perfectly pleasant, served on a bed of shredded cabbage. This was served with decent rice, pickled cucumber and tomatoes, mustard and some rather superfluous fried florets of cauliflower.
It is obviously tricky to judge a restaurant entirely on a bento box lunch for one, but what I ate was 2/10 standard, and at just $15 was fair value for money. Service was efficient and friendly, and the food arrived quickly. If you are looking for a decent value, competent lunch near the Ferry Building you could do much worse.