Geography of Taiwan and Green Island to the southeast, separated from the northernmost islands of the Philippines by the Bashi Channel. The islands of Kinmen and Matsu near the coast of Fujian across the Taiwan Strait have a total area of ; the Pratas and Taiping islets in the South China Sea are also administered by the ROC, but are not part of the Taiwanese archipelago. The island of Taiwan was formed approximately 4 to 5 million years ago at a complex convergent boundary between the Philippine Sea Plate and the Eurasian Plate. In a boundary running the length of the island and
Free area of the Republic of China China" or simply the "Taiwan Area". The term "Tai-Peng-Kin-Ma" is also essentially equivalent except that it only refers to the four main islands of the region - Taiwan, Penghu, Kinmen and Matsu, to the exclusion of the South China Sea area possessions. The term is opposed to "mainland area", which is practically viewed synonymous to mainland China. The term "free area" or "Free China" was used during the Second Sino-Japanese War (1937–45) to describe the territories under the control of the Kuomintang (KMT) government in Chongqing (at the time romanized as Chungking), as opposed to the parts of China under