This stamp is not so simple.There are pages & pages in books just about the 40 pen stamp.Yours has vertically laid paper.The 40 pen was very often poorly printed.
Is it mint with gum ?
Yours is genuine judging from the secret marks and corner petal configurations.
You can learn just as much from faulty stamps as from VF stamps.
Some collectors only collect faulty stamps.Finding cheap faulty stamps
of high values is not so easy and sometimes impossible.These Finnish stamps are often faulty to very faulty(like yours).
1) small break in the inner oval.
2) line connecting the bottom right leg of the H and parenthesis.