Mass franking and single franking 20 Mark dark brown violet postage stamps issue 1922 on cover from Knurow to Chemnitz, ZKr KNUROW 12.7.1922, transit postmark oval railway cancel (TPO) Wroclaw railway mail 14.7.1922 and arrival postmark Zkr CHEMNITZ 15.7.1922 both at back, the letter durchlief the foreign currencies check in Wroclaw: violet official stamp post monitoring place Wroclaw (in the OS handbook unlisted), time typical traces of age and usage