Extended Work, Night Work and Holiday Work (Article 56 of the LSA)
1) Night work means the work provided from 10 p.m. to 6 a.m., and holiday work means the work exempt from duty to provide labor stipulated by the law, collective agreement, Rules of Employment (ROE) or labor contract.
2) Calculation method of ordinary wages
The term “ordinary wages” means hourly wages, daily wages, weekly wages, monthly wages, or contract wages that are determined to be paid periodically or in lump sum to an employee for his/her prescribed work or whole work.
①        In the case of wages determined on an hourly basis, the amount of the hourly wages;
②        In the case of wages determined on a daily basis, the amount calculated by dividing the daily wages by the number of contractual working hours per day;
③        In the case of wages determined on a weekly basis, the amount calculated by dividing the weekly wages by the number of hours based on which weekly ordinary wages are calculated ;
④        In the case of wages determined on a monthly basis, the amount is calculated by
dividing the monthly wages by the number of hours (one-twelfth of the number
of hours calculated by multiplying the number of hours based on which weekly
ordinary wages are calculated by the average number of weeks in the year) based on
which monthly ordinary wages are calculated ; and
⑤In the case of wages determined under a contract wage system, the amount calculated by dividing the total sum of wages under that contract wage system during the period for wage calculation by the total number of working hours during that period.
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Article 56 (Extended, Night or Holiday Work)

An employer shall, in addition to the ordinary wages, pay 50 percent or more thereof for extended work (work during the hours as extended pursuant to Articles 53 and 59 and the proviso to Article 69), night work (work between 10:00 p.m. and 6:00 a.m.), or holiday work.