This is Thiele II Dark redbrown.
determining the right print is required to be able to fully plate it.
Ferlev and thiele I + II uses plate I and II, Thiele III uses plate III and IV.
for plating these issues there are 3 small books (old books, but in both danish and english). There is also a small section in the specialized danish AFA special (not that good and not in english)
Facit is probably the best option as an english speaker - but really inaccurate.
best way to get those 3 books is keep an eye on danish auctionhouses or perhaps eBay
in regards to telling which print apart.
ferslev, thiele I and II, are quite dark, to tell thiele I from the others you look at the burlage in the paper, which is very faint to non existant.
the others have clear burlage, ferslev has kobberburlage which is sort of "on top of the paper" so it's often visible in the cancellation. thiele II is worn plates, and one is very dark towards black, so if's not like that, and has no burlage like ferslev or thiele I, it's a dark redbrown.
telling thiele III apart requires experience and reference material.
another interesting thing with your stamp is that it has a grain of sand in the paper, these often fall out and are wrongly referred to as pinholes.