Last night my family wanted to go to a restaurant, but when we got there, it was closed. On the door, it stated that the restaurant was closed the first Monday of every month. It really puzzled me - is it a financial/cultural/business/personal thing? I know the owners are Asian (but from what part I couldn’t tell you), but there’s a fish and chip shop (Greek-owned) I know of that is closed every Monday (not just the first Monday of the month).
Many serious restaurants (as opposed to fast-food joints), of many different ethnicities, are closed Mondays, as the chef(s) work hard on Fridays, Saturdays, and Sundays, weekends being the restaurant’s biggest days.
Small restaurants are usually run seven days a week by the owners themselves. Weekends tend to be busiest and they wouldn’t want to be closed too often, so perhaps they’ve just decided to take one day off per month for a mandatory rest.
When I worked in a restaurant we might take one day a month to completely take the kitchen apart and scrub it floor to ceiling, appliances, rarely used utensils, and the spaces normally out of reach to daily cleaning et cetera. This was usually done after hours rather than during normal business hours.
tarpal - Sushi requires very fresh fish. If the fish markets in your area are closed on Sunday, that would explain why the sushi bars might be closed on Monday. The restaurants can obtain food for regular Japanese meals, but they probably don’t want to make sushi out of two-day-old fish.
I wouldn’t eat any kind of seafood at a restaurant on a Monday, anyway (or a Friday, Saturday, or Sunday), not anymore (having undergone three bouts of food poisoning from week-end seafood since 1997), not unless it was at a sushi bar, where it’s their business to have the best fish around.