If you mean the Greater East Asia Co-Prosperity Sphere - then the nations that are involved on the time are the following:
China
United States Colony - the Phillipines
French Colony -Indochina
Thailand
British Colony - Malaya, Singapore and Hong Kong
Dutch Colony - Indonesia
But if you are referring to the countries that exists today that were once part of Greater East Asia Co-Prosperity Sphere, then these nations are the ff:
China
North and South Korea
Taiwan
Philippines
Vietnam
Cambodia
Thailand
Malaysia
Singapore
Indonesia and
Myanmar
