Briefly describe the traditional way of territorial change.

Before the formation of modern international law, the change of national territory was mainly carried out in five ways considered by traditional international law, namely, preemption, prescription, dependence, cession and conquest.

Preemption: A country consciously acquires land sovereignty that did not belong to any other country at that time.

The subject of preemption must be the country, and the object must be the land that does not belong to any country. The completion of preemption must realize effective possession.

Attachment: refers to the increase of land through new formation, which may be only the change of the existing national territory or the expansion of the existing national territory, which naturally occurs due to attachment. Attachment is the original way to acquire territory, including natural attachment and artificial attachment. No country may change the natural state of its own territory to the detriment of the natural state of its neighboring territory.

Restriction: a country's long-term, uninterrupted and open possession and rule over part of another country's territory in order to obtain the sovereignty of that part of the territory.

Prescription is not based on "goodwill", as long as possession is long-term, uninterrupted, open and stable. Under the current international law, prescription is certainly not an effective basis for acquiring territory, and the concept of prescription is mainly applicable to solving territorial problems left over from history.

Cession: A country transfers its territorial sovereignty to another country by treaty.

In principle, any country can cede part of its territory to another country, or even cede all its territory to another country and merge with it. The cession is based on the treaty, and there are two kinds of compulsory cession and non-compulsory cession.

Conquest: After the war, the conquering country annexed all or part of the territory of the conquered country.

Conquest is a way to acquire territory only when the conquering country firmly establishes conquest, the state of war is over, and then the territory is formally annexed.