In Japan, sushi is considered a lunch dish. They demand their fish so fresh, that they consider it too old by dinner time (and that's caught that morning and kept on ice).
“In Japan, sushi is considered a lunch dish.”
Sorry, urban legend. You just can’t get a bluefin tuna from the water to the plate in one morning.
Besides, some sushi toppings are himono, sun dried seafood. Smells like bait after a week on the pier.
I can only tolerate freshness down to about 95 (on a scale of 1 to 100). Japanese regularly eat stuff that registers about 3 on that scale.