ThAn Jung-geun, who assassinated the Japanese prime minister in Korea, believed in the union of China, Korea, and Japan in order to counter and fight off European Colonialisn and interference, considering the trajectory that Asian history took, it clearly did not happen.
Your challenge, with a POD as far back as possible, if you choose to accept it, is to create and make pan-asianism a viable force in the late 19th and 20th centuries.