A familiar orange and green signboard glares in the pitch-dark, quiet street in a residential area. There, the owner of a 7-Eleven franchise store located in the suburbs of a small city in the Chubu region works the night shift every day by himself.

The owner, in his 40s, said he works 500 hours a month. He consulted with the Labor Standards Inspection Office, only to be told that it doesn't deal with complaints from owners.

When his wife works with him, the couple keep their 6-year-old son and 4-year-old daughter in a room at the back of the store and let them play games or watch videos using a smartphone.