Weihaiwei in the context of Wendeng, Shandong

The First Sino-Japanese War (25 July 1894 – 17 April 1895), or the First China–Japan War, was a conflict between the Qing dynasty of China and the Empire of Japan primarily for influence over Korea. In Chinese it is commonly known as the Jiawu War. After more than six months of unbroken successes by Japanese land and naval forces and the loss of the ports of Lüshunkou (Port Arthur) and Weihaiwei, the Qing government sued for peace in February 1895 and signed the unequal Treaty of Shimonoseki two months later, ending the war.

In the late 19th century, Korea remained one of the Qing tributary states, while Japan viewed it as a target of imperial expansion. In June 1894, the Qing government, at the request of the Korean emperor Gojong, sent 2,800 troops to aid in suppressing the Donghak Peasant Revolution. The Japanese considered this a violation of the 1885 Convention of Tientsin, and sent an expeditionary force of 8,000 troops, which landed at Incheon. This army moved to Seoul, seized the Korean emperor, and set up a pro-Japanese government on 23 July 1894 in the occupation of Gyeongbokgung. The Qing government decided to withdraw its troops, but rejected recognition of the pro-Japanese government, which had granted the Imperial Japanese Army the right to expel the Qing's Huai Army from Korea. About 3,000 Qing troops still remained in Korea, and could be supplied only by sea; on 25 July, the Japanese Navy won the Battle of Pungdo and sank the steamer Kowshing, which was carrying 1,200 Qing reinforcements. A declaration of war followed on 1 August.