This status was retained until 1912, when the superior prefecture was abolished and the city became a county seat. 19th and early 20th centuries In the late 19th century Changde became a prosperous commercial center and the chief agricultural central market of the Yuan River basin. Many Chinese firms, and — after 1905, when it was opened to foreign trade — foreign firms as well, maintained branches there to buy rice, cotton, tung oil, and timber, so that Changde's economic influence reached out into northern Guizhou, southwestern Hubei, and parts of southeastern Sichuan province. The merchants of the Taho quarter of the city controlled much of the northwestern Hunan economy, and early in the 20th century Changde was the second city of Hunan, after Changsha. Second World War In the 1943 Battle of Changde, the Kuomintang's National Revolutionary Army attempted to stop the invading Imperial Japanese Army from completing their invasion of Sichuan. Frustrated, the Japanese side employed chemical weapons to clear their way. During the Khabarovsk War Crime Trials, proof was presented of operations to contaminate the area with plague as early as 1941 and 1942. People's Republic Although the commercial dominance of Changde firms disappeared with the advent of communist rule in 1949, the city remained an important center of trade, with the majority of its population engaged either in commerce or in transportation. In 1975, Changde was hit by Typhoon Nina. Geography Located on the Yuan River upstream from its junction with the Lake Dongting system, Changde is a natural center of the northwest Hunan plain. The city was historically situated on the north bank of the Yuan River, and has since expanded development south of the river. The Chinese phrase "" (literally "Three mountains and three rivers") is often used in reference to the general physical geography of the city. Around the city are three nearby mountains- Taiyang Mountain () to the north, Mount De () to the south, and Mount Hefu () in the west. In addition to the Yuan River, the city has plentiful water resources with the Chuanzi and Xin Rivers both flowing through Wuling urban district. The other major geographic feature of the area is Liuye Lake (), to the northeast of the city center. There are also numerous lakes, ponds, and streams in the city although many have been diverted or buried. The larger prefecture-level city of Changde is adjacent to