The Flag of the Republic of China, a state commonly known as Taiwan was first used in mainland China by the Kuomintang (KMT, the Chinese Nationalist Party) in 1917 and was made the official flag of the ROC in 1928. Since 1949, the flag is mostly used within Taiwan where the Republic of China relocated after having lost the Chinese Civil War to the Communists.
The three colors of flag correspond to the Three Principles of the People:
- Blue represents nationalism and liberty.
- White represents democracy and equality; and
- Red represents the people's livelihood and fraternity;
In the "Clear Sky with a White Sun" flag of Lu Hao-tung, the twelve rays of the white Sun symbolize the twelve months and the twelve traditional Chinese hours, each of which corresponds to two modern hours. Sun Yat-sen added the "Red Earth" to the flag to signify the blood of the revolutionaries who sacrificed themselves in order to overthrow the Qing Dynasty and create the ROC. (source)
Thank you Patty!