In 1895, the Qing dynasty lost a war with Japan, and gave Taiwan to Japan.In 1945, the U.S. occupied Taiwan during WWII and put the ROC in charge of administering the occupied territory.In 1952, Japan signed a peace treaty relinquishing claim to Taiwan, but they did not give it to the PRC or the ROC.Taiwan was never reunified with China in any official capacity, no mater what Chiang-kai Shek said in 1945.  In 1945, Taiwan was a U.S. occupied part of Japan.