For 200 years China did nothing with Taiwan. The Ming dynasty called it a ball of mud in the water not worth the effort of the Chinese people. The Qing dynasty did not allow anyone to travel to Taiwan because it was too unsafe to travel. The few people in Taiwan were constantly fighting with the local population. They failed to rule or control Taiwan. For 7 years prior to Japan invading they decided to call it a province. Despite having no control over it. Japan even said they were not convinced Taiwan belonged to China because there was next to nothing there, they put up no fight, and fled before Japan arrived. The PRC also called Taiwan an independent nation and advocated for Taiwan independence until the 1940s when the ROC took control of the island as the request of the allied forces who requested ROC administer Taiwan until they decided what to do with the island, because no one was convinced it ever belonged to China to begin with.