What was the Greater East Asia Co-Prosperity Sphere?

Germany had "Fortress Europe", Japan had the "Greater East Asia Co-Prosperity Sphere." Each a name for their finished conquests.

According to my U.S history book, it says "In 1940, Japan's prime minister announced a Greater East Asia Co-Prosperity Sphere to be led by the Japanese, extending from Manchuria in the north to the Dutch East Indies in the south. Japan declared it would liberate Asia from European colonizers..." (Prentice Hall America Pathways to the Present [Texas Edition], PG. 584)