 Complete the following phrase:  The tournament started as the German Open and was a ranking tournament from 1995 to 1997. The event was held in Frankfurt, Osnabrück and Bingen am Rhein in its first three years. In 1998 the name of the tournament was changed to German Masters, and it became a non-ranking tournament. The event then was discontinued, but returned for the a hrefSnooker20season202010201120102011 seasona as a ranking tournament. It has been held at the Tempodrom in Berlin since the 