China's claims of sovereignty over Taiwan are a "bluff," pure and simple. Such claims do not rely on any true legal foundation.
Unfortunately however, although many legal researchers in North America, Europe, Japan, etc. fully realize that Taiwan does not belong to China, nevertheless they are unable to precisely define to whom Taiwan currently "belongs." This failure on their part is largely due to the fact that they are unfamiliar with "the customary laws of warfare of the post-Napoleonic period."
With an in-depth knowledge of these customary laws, it is possible to create an accurate "Introduction and Outline for Modern Taiwanese History" which explains all relevant details. As of early 2007, such an Introduction and Outline was completed by researchers in Taiwan, and is available online at
http://www.taiwanbasic.com/civil/tmodhiae.htm
The San Francisco Peace Treaty (SFPT) of April 28, 1952, is the highest ranking document of international law, and of United States law, which deals with the legal status of Taiwan in the post WWII era.
A "laws of war" reading of the SFPT, along with some basic research into the military history of Taiwan beginning in the late 1930's, reveals the following facts:
The Republic of China on Taiwan is a (1) subordinate occupying power, beginning Oct. 25, 1945, and (2) a government in exile beginning mid-December 1949.
In relation to Taiwan, the United States of America is the principal occupying power, and United States Military Government (USMG) jurisdiction over Taiwan has begun as of the surrender of Japanese troops on Oct. 25, 1945. Today, Taiwan remains as occupied territory of the United States of America.
USMG jurisdiction over Taiwan is currently active.