Sābisu zangyō, service overtime, is overtime work that is not paid. In a survey reported in 2015 by Rengo, the Japanese Trade Union Confederation, about 40 percent of workers said that they had been in a situation where they had to do it. The average was 16.7 hours a month.
Tsukiai zangyō, keeping-company overtime, means staying at work after one’s own tasks are done, to match colleagues or the boss. In a survey by the Ministry of Health, Labour and Welfare, 12.8 percent named ending it, with bosses sending staff home early, as a measure needed to reduce overtime.