The Japanese Combined Fleet secured command over the Yellow sea after defeating the North Sea-Suishi (an old word for the Navy) of the Qing Dynasty (the China North Sea fleet) during the battle of Kokai Kaisen (a naval battle that took place at the mouth of the Yalu River) which started at 12:50 on September 17.
日本の連合艦隊と中国清朝の北洋水師（中国北洋艦隊）との間に黄海上で9月17日12時50分より行われた黄海海戦(日清戦争)で、黄海の制海権を確保した。