During the war, the only military formations larger than the Army Group were the Military Regions, which were defined by geographical boundaries, and the Army Corps, of which only four were only formed and only during the Battle of Wuhan. In effect, the Army Group was the largest fighting unit of the National Revolutionary Army, and usually exercised command over two or more armies or several corps, and assorted lesser units. They were roughly equivalent in size to an Army in British or American military terminology. By the end of the war with Japan, 40 Army Groups were in existence. The civil war saw three additional Army Groups being formed, even as they were gradually being replaced by newly formed Army Corps, by then a largely analogous formation. The following list provides an overvie