The Battle of the Yalu River (; ; ) was the largest naval engagement of the First Sino-Japanese War, and took place on 17 September 1894, the day after the Japanese victory at the land Battle of Pyongyang. It involved ships from the Imperial Japanese Navy and the Chinese Beiyang Fleet. The battle is also known by a variety of names: Battle of Haiyang Island, Battle of Dadonggou, Battle of the Yellow Sea and Battle of Yalu, after the geographic location of the battle, which was in the Yellow Sea off the mouth of the Yalu River and not in the river itself. There is no agreement among contemporary sources on the exact numbers and composition of each fleet, but both were of a similar size, and the battle is considered to be one of the Imperial Japanese Navy's greatest victories. Background Japan's strategy Japan's initial strategy was to gain command of the sea, which was critical to its operations in Korea. Command of the sea would allow Japan to transport troops to the mainland. The Imperial Japanese Army's Fifth Division would land at Chemulpo on the western coast of Korea, both to engage and push Chinese forces northwest up the peninsula and to draw the Beiyang Fleet into the Yellow Sea, where it would be engaged in decisive battle. Depending on the outcome of this engagement, Japan would make one of three choices; If the Combined Fleet were to win decisively, the larger part of the Japanese army would undertake immediate landings on the coast between Shan-hai-kuan and Tientsin in order to defeat the Chinese army and bring the war to a swift conclusion. If the engagement were to be a draw and neither side gained control of the sea, the army would concentrate on the occupation of Korea. Lastly, if the Combined Fleet was defeated and consequently lost command of the sea, the bulk of the army would remain in Japan and prepare to repel a Chinese invasion, while the Fifth Division in Korea would be ordered to hang on and fight a rearguard action. Chinese moves With tensions with Japan increasing over the situation on the Peninsula, the Chinese government chartered three steamers to carry reinforcements to Korea in late July to bolster their position in Korea. The three troopships were escorted by three naval vessels, the cruiser and the gunboats Kwang-yi and . A Japanese force