In 1940 the Hungarian Ministry of De fence to obtain Czechoslovakian tanks, but the production from Skoda and CKD/Praga were committed to building tanks for the Germans. They did obtain the production rights to the Czechoslovakian designs for the S-IIr, S-IIa, T-21.
The S-IIr prototype was completed in August 1941. Production for the Turan 1 started in October 1941.
They were built by the Weiss & Cspel Steelworks of Budapest.
A long barrel 75 mm gun was installed. It was only in the prototype stage when the Germans occupied Hungary. It was to be called the Turan 3.
The 2 man turrets were replaced by 3 man turrets and radios. The Hungarian made 8-cylinder engine was installed. This became the 40M Turan I.