Basic 2-Shift Model in Japan

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This project is an example project for typical 2 Shifts Pattern in Japan.


Shift Hours
Day Shift 8:00- 17:00
Night Shift 16:30- 9:00
  1. 18 staff
  2. Two night shift staff every day
  3. RN is greater or equal to one on Night Shift
  4. At least 10 staff on weekday day shifts
  5. 5 staff on day shift on weekends and holidays
  6. Night shift frequency will be equalized as much as possible
  7. Moderate intervals between night shifts to prevent overconcentration of night shifts
  8. Six consecutive days of work is prohibited
  9. At least 1 consecutive Saturday and Sunday off
  10. One day off after night shift
  11. 9 Day-Offs per month



The night shift is divided into night shift 1 and night shift 2.

Cover Costraints

Staff Property

Group Set

Row Constraints

Basic 2-Shift Pattern

The night shift is divided into night shift 1 and night shift 2. Since night shifts work across days, night shift 1 is a virtual shift, with night shift 1 representing the first day of night work and night shift 2 representing the next day’s work. Therefore, night shift 1 and night shift 2 always work in pairs, and the pattern must be written so that night shift 1 is followed by night shift 2, and night shift 2 is followed by a day-off.

Equalized Constraints

The first constraint is the maximum consecutive pattern as usual. Excessive consecutive shifts may occur not this month but the next month if we do not implement the second constraint.

The third through sixth constraints above are intended to moderate the interval between night shifts. The longer the interval between night shifts, the more restrictive the constraint becomes. Therefore, the fifth through sixth constraints are soft constraints.

Solve it!


Project File

File → Open Project File from Github