On February 1, 2016, a milestone day, the five major theaters of the Chinese People's Liberation Army made a new appearance, and the former seven major military regions quietly withdrew from the historical stage. 
A military region, also known as a large military region, is a solid shield of the state, a first-level organization of the armed forces that is carefully laid out according to the country's administrative region, geographical location, strategic campaign direction, combat mission, and other factors, and is the highest military leadership and command organ in a strategic region. They are usually named after the location of the leading authority, the jurisdiction, the geographical location, or the ordinal number, symbolizing stability and strength. In times of war, military regions are the core of leading and directing all armed forces in their strategic zones and directions, ensuring that all forces of all sides work together to form a powerful combat force. In peacetime, however, the military region shoulders the heavy responsibility of leading and guiding the command of joint operations of all branches of the armed forces within its jurisdiction and the military training, political work, administrative management, and logistical support of the units under its jurisdiction. In addition, it leads the militia, military service mobilization and battlefield construction in its jurisdiction, ensuring that the army always maintains high morale and combat effectiveness. It can be said that the military region is the leading organ of the synthesis of the main arms of our army at the highest level, and it is a strong backing for the defense of the armed forces. 
After the founding of the People's Republic of China, along with the continuous development of military struggles and army building, the PLA has also undergone many adjustments in its large military regions. These adjustments can be roughly divided into three periods: the period of the six major military regions in the early days of the founding of the People's Republic of China, when New China had just been established and faced with a complex domestic and foreign environment, and the six major military regions guarded the country's tranquility like a great wall of steel; From 1955 to 1985, the number of large military regions was gradually adjusted from 12 to 11, and the adjustment during this period reflected the profound changes in the country's military strategy. In 1985, when the million-dollar disarmament was carried out, the number of large military regions was adjusted to 7, which marked the development of the squadron in a more capable and efficient direction. Each of these adjustments has witnessed the growth of the country and the progress of the army.