[ROC Passport] ROC nationality for Taiwanese persons

I received an email approximately a month ago asking for clarification as to why the “Taiwanese persons” domiciled in Taiwan in 1945 and their decendants are considered to be ROC citizens.

I have to admit that the more I research this question, the more confused I am becoming.

For details on this, Nationality Law goes back to 1929. (That was later amended in February 2000.)

Article 10 of the Treaty of Peace between the Republic of China and Japan (commonly called the “Treaty of Taipei”) provides that —
*For the purposes of the present Treaty, nationals of the Republic of China shall be deemed to include all the inhabitants and former inhabitants of Taiwan (Formosa) and Penghu (the Pescadores) and their descendents who are of the Chinese nationality in accordance with the laws and regulations which have been or may hereafter be enforced by the Republic of China in Taiwan (Formosa) and Penghu (the Pescadores) . . . *

Considerations: (1) As stated above, the Nationality Law goes back to 1929. It was not changed in the post WWII era to reflect any consideration that “all persons in Taiwan [of certain ethnic characteristics] are NOW to be considered ROC nationals.” Based on this fact, it would appear that there is no basis in the Nationality Law for stating that inhabitants of Formosa and the Pescadores (after October 25, 1945) are ROC nationals.

(2) Japanese Courts have typically held that persons native to Taiwan ceased to be Japanese nationals as of April 28, 1952. The Treaty of Taipei entered into force on August 5, 1952.

(3) For comparison, when Formosa (Taiwan) and the Pescadores were ceded to Japan by China, the Treaty of Shimonoseki, which entered into force on May 8, 1895, specifically provides in the first paragraph of Article 5 that —
The inhabitants of the territories ceded to Japan who wish to take up their residence outside the ceded districts shall be at liberty to sell their real property and retire. For this purpose a period of two years from the date of the exchange of ratifications of the present Act shall be granted. At the expiration of that period those of the inhabitants who shall not have left such territories shall, at the option of Japan, be deemed to be Japanese subjects.

I have been unable to find any other legal or treaty references which can serve as the basis for saying that all inhabitants of Formosa and the Pescadores “are hereby considered to be ROC nationals” [after a certain date.] I would appreciate any comments relevant to this research.