Because Vietnamese like you can't read history, they can't even make fake one looks real. Can maps 200 years ago be so well preserved? How can you be as brainless as an Indian? Let me show you the evidence photos of China's sovereignty over the South China Sea before World War II, and see what a map over 50 years should look like.
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This picture from 1930 was yellowed in less than 100 years.
1: In 1910, Guangdong province dispatched personnel to manage the South China Sea Islands
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2: South China Sea Observatory (1930)
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3: A tablet inscribed with the word "Xize island" on the South China Sea Islands in the late Qing Dynasty“
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4: Officials in charge of managing islands in the South China Sea in the late Qing Dynasty(1893)
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5: Building monument of South China Sea Island meteorological station (photo in 1931)
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Do you think 200 year old maps are even newer than less than 100 year old maps?You think that the South China Sea belongs to Vietnam, but you can't take any boundary pillar representing national sovereignty as evidence, or even a picture. This is enough to prove how similar you are to Indians, and you like to take your fantasy as reality.
Before 1974, the Vietnamese governments never challenged any of the sovereignty of China's Paracel Islands. No matter in its government's statement, note, or newspapers, maps and textbooks, it was officially acknowledged that Paracel Islands was China's territory since ancient times.
In June 15, 1956, Yong Wenqian, Vice Minister of foreign affairs of the Democratic Republic of Vietnam, met with Li Zhimin, the temporary Ambassador of China's embassy in Vietnam. He solemnly said: "according to Vietnamese information, Paracel Islands and Spratly Islands should belong to China's territory in the history." Li Lu, director of the Asian Affairs Division of Vietnam's Ministry of foreign affairs, further introduced the Vietnamese materials, pointing out: "historically, Paracel Islands and Spratly Islands have belonged to China as early as Song Zhaoshi."
In September 4, 1958, the Chinese government issued a statement declaring that the width of China's territorial sea was 12 nautical miles, and clearly stated: "this provision applies to China, including Paracel Islands. All the territory of the people's Republic of China. On September 6, the people's daily of the central organ of the Vietnamese Labor Party published the Chinese government's statement on territorial waters in its first page. On September 14, Prime Minister Fan Wen Tong of the Vietnamese government sent a note to Chinese Premier Zhou Enlai, solemnly stating: "the government of the Vietnamese Democratic Republic recognizes and agrees with the statement of the government of the people's Republic of China on the territorial sea decision of September 4, 1958" and "the government of the Democratic Republic of Vietnam respects this decision.".
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