text: what does this japanese clause mean? 勤務日数は週５日を原則とし、休日は、毎週土・日曜日及び国民の祝日とする。ただし、甲は、業務の都合により、４週間を通じ８日の範囲内であらかじめ定めるところにより、休日を変更して勤務を命じることがある。  i can actually understand that the first sentence is talking about national holidays and day offs. however, i don't know about the "4 weeks" and the 8 days in the second sentence.thanks a lot for your help it means that 甲 (should have been defined in the previous part of the document; probably the employer) may change the days off (from the usual sun, sat and national holidays) but the change must not involve more than eight days our of four weeks.