Gyodon shops can minimize labour by having customers pay at a vending machine.
Mid-afternoon, Diana and I checked into the Courtyard Tokyo Ginza on frequent stay hotel points for the week.1 We were hungry, having foregone taking sandwiches onto the train, in favour of a better meal in Tokyo. Since the hotel is near Tsukiji, we headed that direction even though we expected most stores would be closed. We found our first of many gyudon (beef bowl) shops.
The signs and sample dishes outside were encouraging. If we ran into problems ordering from a server, we could pull him or her outside and point. With dishes in the range of $5 to $8 per serving, the price was right.