Because of the restrictions imposed on the Germans by the Treaty of Versailles, they were forbidden to build new tanks. The shaky Weimar government was only too willing to toe the line, so in 1930 the Provisional Reichswehr took matters into their own hands.
They actually made a clandestine deal to buy tanks from the Soviets. This picture shows Russian tankers delivering a shipment of T-26 “English Workmen”. The guy who took the photo, a Feldgendarm of Dutch extraction (I assume) named Gerrit von Rothenburg, was very nearly kicked out of the army for taking a picture of a secret deal. He went on to die in Libya in ‘42.
Also, does anyone else think it’s kinda funny that the Germans made a deal to buy Russian tanks copied from an English (Vickers) design? Well, I do.
photo (c) Gerrit von Rothenburg, 1930