Inner Asia is a term referring to particular regions within Asia. It has a major overlap with some definitions of Central Asia, mostly the historical ones, but certain regions of Inner Asia (such as Manchuria) are not considered a part of Central Asia by any of its definitions. One way to think of Inner Asia is as the "frontier" of China, and as bounded by East Asia (consisting of China, Japan, and Korea). The actual extent of Inner Asia may be different during different periods in history. In 1800 it consisted of four main areas, namely Manchuria (modern Northeast China and Outer Manchuria), Mongolia (Inner and Outer), Xinjiang and Tibet. All were part of the Qing dynasty and were garrisoned by Qing forces, but they were governed through several different types of administrative structure and not as regular provinces during most of the Qing period. The Qing government agency known as the Lifan Yuan was established to supervise the empire's Inner Asian regions.