ROC flag 1912- 1928
ROC flag 1928 - 1949
The Republic of China (ROC) was a sovereign country that existed between 1912 and 1949 in Mainland China, which is now the People's Republic of China. It was established in January 1912 after the Xinhai Revolution, which overthrew the Qing dynasty, the last imperial dynasty of China. The Republic's first president, Sun Yat-sen, served only briefly before handing over the position to Yuan Shikai, the leader of the Beiyang Army. Sun's party, the Kuomintang (KMT), then led by Song Jiaoren, won the parliamentary election held in December 1912. However, Song was assassinated on Yuan's orders shortly after; and the Beiyang Army, led by Yuan, maintained full control of the Beiyang government. Between late 1915 and early 1916, Yuan Shikai was the self-proclaimed Emperor of China before abdicating due to popular unrest. After Yuan's death in 1916, the authority of the Beiyang government was further weakened by a brief restoration of the Qing dynasty. Cliques in the Beiyang Army claimed individual autonomy and clashed with each other during the ensuing Warlord Era.
In 1921, Sun Yat-sen's Kuomintang established a rival government in Canton, supported by the fledgling Communist Party of China (CPC). The economy of North China, overtaxed to support warlord adventurism, collapsed between 1927 and 1928. General Chiang Kai-shek, who became the KMT leader after Sun's death, started the Northern Expedition in 1926 to overthrow the Beiyang government, which was accomplished in 1928. In April 1927, Chiang established a nationalist government in Nanjing, and massacred Communists in Shanghai. The latter event forced the CPC into armed rebellion, marking the beginning of the Chinese Civil War.
China experienced industrialization and modernization but suffered conflicts between the Nationalist government in Nanking, the CPC, remaining warlords, and the Empire of Japan. Nation-building efforts yielded to having to fight the Second Sino-Japanese War, when the Imperial Japanese Army launched an offensive against China in 1937 that turned into a full-scale invasion. In 1946, after the surrender of Japan at the end of World War II in 1945, the Chinese Civil War between the KMT and CPC resumed, leading to the 1946 Constitution of the Republic of China replacing the 1928 Organic Law as the Republic's fundamental law. In 1949, near the end of the Civil War, the Chinese Communist Party established the People's Republic of China, overthrowing the nationalist government on the Chinese mainland, with the nationalists moving their capital from Nanking to Taipei and controlling only the Taiwan area after 1949.
Adapted from Wikipedia.