A chess set made of cast iron by E.G.Zimmermann in Hanau. It is the type known as "The 30 Year War" and similar to the set shown here, including the Zimmerman imprint on the underside of the kings. However, this is a more luxurious and rarer version. While in the simpler version, the white side is simply lacquered in silver and the black side is in pure cast iron, in this more elaborate version the two sides are plated, i.e. silver-plated for the white side and the copper-plated for the black side. Silver- and copper-plating for Zimmermann sets is not unknown, but these sets are quite rare. 

In addition, while the simpler version comes in a compartmented paper box, this more elaborate version comes in a fitted case lined with purple velvet on the inside.