Ten dollars banknote, Hong Kong & Shanghai banking corporation, China, 1948; Size: 183 mm x 105 mm; Condition: fine; Provenance; private collection in Tampa, Florida, USA The customs gold unit (CGU) was a currency issued by the Central Bank of China between 1930 and 1948. In Chinese, the name of the currency was 關金圓 guānjīnyuán, literally "customs gold yuan" but the English name given on the back of the notes was "customs gold unit". It was divided into 100 cents (關金分). As the name suggests, this currency was initially used for customs payments, but in 1942 it was put into general circulation for use by the public at 20 times its face value in terms of the first Chinese yuan. The Republic of China (ROC) during 1912 to 1949, commonly known as China, was a sovereign state based in mainland China prior to the relocation of its government to Taiwan. At a population of 541 million in 1949, it was the world's most populous country. Covering 11.4 million square kilometres (4.4 million square miles),[3] it consisted of 35 provinces, 1 special administrative region, 2 regions, 12 special municipalities, 14 leagues, and 4 special banners. This period is sometimes referred to as the Republican Era[4] or the Mainland Period.[5] The Republic was declared on 1 January 1912 after the Xinhai Revolution, which overthrew the Qing dynasty, the last imperial dynasty of China, ending 5,000 years of monarchy in China.[citation needed] Sun Yat-sen, the founder and its president 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, who then proclaimed himself Emperor of China from 1915 before abdicating not long after 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, the KMT established the national government in Guangzhou, supported by the fledgling Communist Party of China (CPC). The economy of Northern China, overtaxed to support warlord adventurism, collapsed between 1927 and 1928. General Chiang Kai-shek, who became the Chairman of the Kuomintang after Sun's death in 1925, 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 some industrialization during the 1930s but suffered setbacks from conflicts between the Nationalist government in Nanjing, the CPC, remaining warlords, and the Empire of Japan. Nation-building efforts yielded to fight the Second Sino-Japanese War, when the Imperial Japanese Army launched an offensive against China in 1937 which turned into a full-scale invasion that lasted until the surrender of Japan at the end of World War II in 1945 and regained control of the island of Taiwan and the Pescadores. Shortly after, 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[6] as the Republic's fundamental law. Three years later, in 1949, nearing the end of the civil war after, the CPC established the People's Republic of China on the mainland, with the nationalists moving their capital several times from Nanjing to Guangzhou, followed by Chongqing, then Chengdu and lastly, Taipei although the Nationalist government controls Taiwan and other smaller islands from 1949 onwards, Hainan until 1950 and Dachen Islands in Zhejiang until 1955. The ROC was a founding member of the League of Nations and later the United Nations (including its Security Council seat) where it maintained until 1971, when the People's Republic of China took over its membership. It was also a member of the Universal Postal Union and the International Olympic Committee.