Long ago a friend and I would go out on bikes for some red lantern hopping for a night out. Working at ICU at the time, so the area where Mitaka, Sakai, and Koganei border each other.
Late edit: I guess I wouldn't call the red lantern places we went to 'snack' bars, instead traditional, cheap and no frills. And we were going for some bits of real food (besides the beer), grilled something or whatever they might offer--shishamo was a common ask, maybe the odd veggie or garlic, and so on. Similarly, when I (or we) have happened (mistakenly) into a snack bar, it always felt like invading someone's personal space.