To Imperial Japan, the sea was an integral part of its total war efforts. Being a state of islands itself, it was imperative for Japan to secure stable means of transportation to the Japanese mainland on the sea, in order to win the World War Ⅱ. Japan was also in need of resources that can be obtained from the sea, so the sea of colonized Korea was perceived and used as a network connecting Japan and China, as well as a pool of usable assets.<BR> Because it has been a region that served as a gateway to Seoul for a long time, development of Incheon and its coastal area began fairly early on, ever since the country was opened to the outer world. Yet its status started to buckle after 1904 when the Capital-Busan Railway service was initiated, and after the Korean sovereignty was lost to Imperial Japan, development of the Incheon region slowed down and fell behind other cities like Busan. Then, the breakout of the China-Japan war was perceived in the eyes of the concerned as an opportunity to restart Incheon’s arrested development. The importance of Incheon was newly evaluated, under the notion that the ‘Yellow Sea’ could connect China, the Korean peninsula and Japan as a “virtual lake.”<BR> Examined in this article is how the development of Incheon progressed under the ‘Making the Yellow Sea a lake’ since the beginning of the China-Japan war, and how the war itself served as a deterrent to such expected development. During wartime the necessity to develop the resourceful Gyeonggi Harbor did surface, but efforts to launch a plan to support that vision in a viable fashion eventually failed due to insufficient financial investments, which shows us that all propaganda for development shouted in the wake of Imperial Japan’s total war were nothing but empty slogans.