M130601a
Cube containing the letters "I-J-B" placed above "GERMANY".
As the "I-J-B" (or "B-J-I") mark was evidently used on items created at the factory of J. Kronester from Schwarzenbach, we can clearly say that whoever used this mark was merely an importer/distributor. One thing that struck me while checking my archive on unidentified marks was that the name J. & I. Block perfectly matches the "I-J-B" mark; please check M230212; it could well be that both marks were used by the same company.
M130601a
Cube containing the letters "I-J-B" placed above "GERMANY".
M130601b
Cube containing the letters "I-J-B" placed above "GERMANY" and "US ZONE".
M130601c
Elaborate alternative, also containing the letters "B-J-I" placed above "GERMANY", all above "US ZONE".