these cancels exist with the letters A, B and R.They were usually
applied on postage due stamps on the issues from 1908 - 1931
There is no relation between stamp and card.
The card was issued by a private group,who asked the german p.o.
for a special cancel.This is possible...
Makanudo,you had put me on the wrong trail:
the stamp is and is not polish !
It is a postage due stamp from Middle-Lithuania.
Issued in 1921 the set...
You are right,it´s a difficult one.But I had a look at
Scott´s.Following to Sc.18 there is a note: "See
Nos.207-10,286.(No such note in Michel !)
Separate names with a comma.