http://www.noritakecollectorsguild.info/bstamps/

Did you post this mark before ?? Someone did !! As importers they used so many marks and variations of them that it is almost impossible to know each one !! I think you should ask at the above site since it is not on any list I have found !! Please come back and update us here !! I am curious as well !!
My feeling is that is a variation of the D 175 mark from the 30`s but I am no expert !!