Who was the Chancellor of West Germany during the 1990 reunification (German Unity) of the two Germanys?

West German Chancellor, Helmut Kohl announced after the fall of the Berlin Wall, a 10-point program calling for the two Germanys to expand their cooperation with the view toward eventual reunification.

In early 1990, a grand coalition was formed under Lothar de Maizière, leader of the East German wing of Kohl's Christian Democratic Union, on a platform of speedy reunification. Then, East Germany's economy and infrastructure underwent a swift and near-total collapse. These two events caused the rapid unification process to begin.

The reunification was not a merger that created a third state out of the two. Rather, West Germany effectively absorbed East Germany. Accordingly, on Unification Day, 3 October 1990, the German Democratic Republic ceased to exist, and five new Federal States on its former territory joined the Federal Republic of Germany. East and West Berlin were reunited, and joined the Federal Republic as a full-fledged Federal City-State.