There are seven annual airspace closures, as published in the AIP Netherlands, section 5.1-4,5.
The dates of the other annual airspace closures will be published per NOTAM:
Point your mouse to the red areas on the map to display the area. Click on an area for details, such as dimensions and coordinates.
HEMS-, SAR- and policeflights are exempted from the annual airspace closures.