Introduction to the Sino-Japanese War of 1894: On July 25, 1894, the Japanese Navy launched an undeclared war and raided Chinese escort ships and troop transports off the coast of Toyoshima, North Korea. The "Gaosheng" merchant ship carrying Qing troops was sunk by a Japanese ship. More than 870 of the more than 1,000 Qing troops on board were killed. The Qing government was forced to declare war on Japan on August 1. On September 17, 1894, the Chinese and Japanese navies encountered each other in the northern waters of the Yellow Sea, and the largest naval battle since the advent of steam battleships broke out. The naval battle lasted more than 5 hours. The Beiyang Navy lost 4 ships and the Japanese Navy also suffered heavy losses. After that, the Beiyang Navy lost its control of the Yellow Sea. After the Battle of the Yellow Sea, the Japanese army divided into two groups. The First Army broke through the Yalu River defense line and contained the main force of the Qing army. The Second Army landed at Huayuankou and went south to capture the Lushun base. The two armies then joined forces to threaten Shanhaiguan and Beijing and Tianjin. In January 1895, the Japanese army launched the Shandong Peninsula Campaign, aiming to completely annihilate the Beiyang Navy. Since the land and sea garrisons were not under each other's control, the land battle was lost and the forts supported the enemy. The Beiyang Navy was trapped on an isolated island and resisted tenaciously until they ran out of ammunition and reinforcements and the entire army was annihilated.