After the foundation of the Republic of China, in 1913 Zhengzhou changed from being a territory directly administered from the capital, (直隶州"zhílìzhōu"), to Zhengzhou County (). In 1920 the Henan Provincial Legislature proposed the set-up of a trading port in the city then in February 1923 the Jinguan Railway came to a halt during the communist led "27 Major Strike" (), which originated in Zhengzhou but was quickly resolved. In March the same year, the State Affairs Conference of the Beiyang Government officially approved the creation of a trading port at Zhengzhou and established a government commercial office to run it. By 1927, the newly founded "Travel Magazine" () published in Shanghai, was already describing Zhengzhou as a 'major northern Chinese metropolis'. Zhengzhou was elevated to city status by warlord Feng Yuxiang in 1928, then in 1931, following the military confrontation between Chiang Kai-shek, Yan Xishan and Feng during the Central Plains War, Zhengzhou once more became a county. During the Second Sino-Japanese War, on June 9, 1938, in order to stop the westward advance of the Japanese Army along the Longhai Railway, Nationalist KMT troops blew up the dikes along the south bank of the Yellow River at Huayuankou () causing the 1938 Yellow River flood.