The Labor Standards Act excludes persons in positions of supervision or management or persons handling confidential affairs from the application for the provisions on working hours, etc. except for midnight work. The criteria for the persons who are excluded from them are, (1) that they have important job contents and responsibilities/authorities, (2) that the working styles are incompatible with the working hours regulations, and (3) that their conditions such as wages, etc. are reasonable. In addition, such an agreement as "the base salary includes overtime for xx hours" is, in principle, invalid. To make valid the wage system where a certain overtime is included (the fixed overtime wage system), part of the wage for ordinary working hours and part of the wage for fixed overtime must be explicitly divided, and the additional wage for the exceeded part must be paid in the case where the actual overtime exceeds the fixed overtime. Besides, an employment contract where "overtime is not paid" is agreed is invalid if it is not for the manager/supervisor.