How long did the Republic of Formosa exist?
Republic of Formosa
five months
The Republic of Formosa survived for only five months.  The Japanese landed near Keelung on the northern coast of Taiwan on 29 May 1895, and in a five-month campaign swept southwards to Tainan.  During the night of 4 June, on the news that the Japanese had captured Keelung, President T'ang and General Chiu fled to Tamsui, and from there sailed for the mainland on the evening of 6 June.  The Japanese entered Taipei shortly afterwards.[10]