When Mao created the notion of the Three Worlds, he included China in the Third World [1]. It was (ostensibly) unaligned, whereas Europe (and to an extent Japan) was aligned, making it Second World. He (via Deng) specifically called out the Third World as underdeveloped.<p>[1] “Speech by Chairman of the Delegation of the People’s Republic of China, Teng Hsiao-Ping, at the Special Session of the U.N. General Assembly: April 10, 1974” (Peking: Foreign Languages Press, 1974).