Originally, when the Northern Wei Dynasty was established, it was thought that he inherited the extinct Jin, which was the orthodoxy of the Central Plains, so he regarded Jin as a new moon, instead of Liu Han of Cao Wei and Xiongnu as orthodoxy.

When the Northern Wei Dynasty determined the system, it felt that it could not be based on the Jin Dynasty, because at this time, although the Western Jin Dynasty was extinct, there was still the Eastern Jin Dynasty, which was southward. If Jin is regarded as orthodox, the Eastern Jin Dynasty of Sima's family is still orthodox, and the Northern Wei Dynasty lost its orthodox position. Therefore, in order to express their own orthodoxy, it is necessary to cancel the orthodox status of the Jin Dynasty and inherit Cao Wei directly from the Northern Wei Dynasty.