Define a period

...

How many working days in year 1976?

Here is the detail of the calculation:

Because 1976 is a leap year, it has 366 days.

Let's remove 52 saturdays and 52 sundays. It remains 262 days.

Now, let's remove 14 public holidays that do not fall during a weekend and we obtain 248 working days in 1976.

Here is the list of these 14 public holidays:

1. New Year's Day : Thursday, 1 January, 1976
2. Coming of Age Day : Monday, 12 January, 1976
3. Foundation Day : Wednesday, 11 February, 1976
4. Shōwa Day : Thursday, 29 April, 1976
5. Constitution Memorial Day : Monday, 3 May, 1976
6. Greenery Day : Tuesday, 4 May, 1976
7. Children's Day : Wednesday, 5 May, 1976
8. Marine Day : Monday, 19 July, 1976
9. Respect-for-Aged Day : Monday, 20 September, 1976
10. Autumnal Equinox Day : Thursday, 23 September, 1976
11. Health and Sports Day : Monday, 11 October, 1976
12. Culture Day : Wednesday, 3 November, 1976
13. Labor Thanksgiving Day : Tuesday, 23 November, 1976
14. Emperor's Birthday : Thursday, 23 December, 1976

And here is the public holiday falling on a weekend:

1. Vernal Equinox Day : Saturday, 20 March, 1976