A 1947 map showed that South China Sea islands & Taiwan belonged to China.

This map was produced by Rand McNally company (founded in 1868) and could be found in the 1947 Collier's World Atlas and Gazetteer.

The map was produced by the west right after WW2 to indicate the true ownership of the South China Sea islands, a.ka Paracel islands (China), and Taiwan (China).  Taiwan was known as Formosa back then.

The west recognized that China owned the South China Sea islands and Taiwan in 1947 but the west flip-flopped on its stance later after the discovery of natural resources in the South China Sea.