 Complete the following phrase:  Clashes between Chinese and Japanese forces at Pungdo and Seongwhan caused irreversible changes to Sino-Japanese relations and meant that a state of war now existed between the two countries. The two governments officially declared war on August 1. Initially, the general staffs objective was to secure the Korean peninsula before the arrival of winter and then land forces near Shanhaiguan. However, as the navy was unable to bring the Beiyang fleet into battle in mid-August, temporarily withdrew from the Yellow Sea to refit and replenish its ships. As a consequence, in late August the general staff ordered an advance overland to the Zhili plain via Korea in order to the capture bases on the Liaodong Peninsula to prevent Chinese forces from interfering with the drive on Beijing. The First Army with two divisions was activated on September 1. In mid-September 17, the Chinese forces defeated at Pyongyang and occupied the city, as the remaining Chinese troops retreated northward. The navys stunning victory in the 