1943 - German "Stamp Day" Postmarked Postal Card

This is a German collector postal card with commemorative postmark.(not stamped, un-mailed, addressee is unknown, reverse - no message)
TOPIC - "Stamp Day" - Postmark - Issue date January 10, 1943
POSTMARK: STUTTGART - Tag der Briefmarke (Stamp Day) 10.1.1943
PRINTER: Bauerdruck, Mannheim ges. gesch. - manila paper
Reverse instructions - Vor dem Zukleben erst falzen und donn nur eine Halfte anfeuchten (Fold before gluing and then moisten only one half)
Instructions to open (vertical, left side on reverse - vertical right side on obverse) - Gummierung hier losen (mit Bleistift aufrollen) - (Loosen gum here (with pencil roll))