1945 After Japan's surrender at the end of World War II, the Republic of China claimed the Paracel and Spratly Islands. The Republic of China sent troops to Itu Aba Island; forces erected sovereignty markers and named it Taiping Island.
1946 France dispatched warships to the islands several times, but no attempts were made to evict Chinese forces.
1947 China produced a map with 9 undefined dotted lines, and claimed all of the islands within those lines.[75] France demanded the Chinese withdraw from the islands.
1948 France ceased maritime patrols near the islands and China withdrew most of its troops.
1951 At the 1951 San Francisco Conference on the Peace Treaty with Japan, the Soviet Union proposed that the Spratlys belonged to China. The delegates overwhelmingly rejected this suggestion. The delegates from Vietnam, which at that time was a French protectorate, declared sovereignty over the Paracel and the Spratly Islands, which was not opposed by any delegate at the conference. China did not attend the conference and was not a signatory of the treaty.
1956 On 15 June 1956, Vice-Foreign Minister Un Van Khiem of the Democratic Republic of Vietnam received Li Zhimin, Chargé d'Affaires ad interim of the Chinese Embassy in Vietnam, and told him that, "according to Vietnamese data, the Xisha and Nansha Islands are historically part of Chinese territory". Le Loc, Acting Director of the Asian Department of the Vietnamese Foreign Ministry was present and specifically cited Vietnamese data and pointed out that "judging from history, these islands were already part of China at the time of the Song dynasty".[76]
1956 Tomas Cloma, director of the Maritime Institute of the Philippines, claimed sovereignty over the northwestern two-thirds of the Spratly Islands, naming his territory Kalaya'an ("Freedomland"). The People's Republic of China, the Republic of China, France, South Vietnam, the United Kingdom and the Netherlands all issued protests. The Republic of China and South Vietnam sent naval units to the islands, though South Vietnam left no permanent garrison. Later in the year, South Vietnam declared its annexation of the Spratly Islands as part of its Ph??c Tuy Province.
1958 The People's Republic of China issued a declaration defining its territorial waters which encompassed the Spratly Islands. North Vietnam's prime minister, Ph?m V?n ??ng, sent a formal note to Zhou Enlai, stating that the Government of the Democratic Republic of Vietnam respected the decision on the 12 nautical mile limit of territorial waters. Both the South Vietnamese government and the communist revolutionary movement in South Vietnam continued to assert that the Spratlys belonged to Vietnam.
1961–63 South Vietnam established sovereignty markers on several islands in the chain.
1968 The Philippines sent troops to three islands on the premise of protecting Kalayaan citizens, and announced the annexation of the Kalayaan island group.
1971 Malaysia issued claims to some of the Spratly Islands.
https://en.wikipedia.org/wiki/Spratly_Islands_dispute