The "Blue Sky with a White Sun" flag of Lu Hao-tung was unveiled in February 1895 in Hong Kong. The twelve rays of the white Sun symbolize the twelve months and the twelve traditional shichen (時辰; shíchén), a traditional unit of time 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. Together, the three colors of the 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. President Chiang Kai-shek proclaimed on the National Day in 1929, "As long as a national flag with Blue Sky, White Sun, and a Wholly Red Earth flies in the land of China, it will symbolize the independence and liberty of the descendants of the Huang Emperor".

The blue-and-white canton of the ROC flag is often used as the party flag of the KMT. The flag has developed a great deal of additional symbolism due to the unique and controversial political status of Taiwan. At one level, the flag represents a clear symbol that Taiwan is not governed by the same government as mainland China, as this flag is different from the flag of the People's Republic of China (PRC).

Meanwhile, because it was formerly used as the flag over all of China, the flag has become a symbol of continuity with the ideals of the Chinese nationalism and Chinese unification movements, and has become a symbol of a connection both historical and current with mainland China. In addition, the flag is derived from the seal of the KMT, and the color of the field of the flag is associated with the KMT party colors.

Some Chinese see the flag as an expression of Chinese nationalism and pride combined with simultaneous disapproval for the current communist regime. Additionally, the flag may symbolize identification with, and admiration for the political thoughts of Sun Yat-sen, and his Three Principles of the People.

One irony is that given the association of the flag with Chinese nationalism in opposition to Taiwan independence, the ROC flag has found an unexpected ally in the People's Republic of China. The PRC has criticized Taiwan independence groups for wishing to change or abolish the ROC flag, and has implied that legal steps to do so would bring a strongly negative reaction from the PRC.

However, the presence of the ROC flag in Taiwan also distinguishes the fact that Taiwan and ROC territorial islands elsewhere fall under jurisdiction of a country separate from th…

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The specific designs of the flag are located in the National Emblem and National Flag of the Republic of China Act from 1928. The ratio of the flag is 2:3, with most of it being red. One-fourth of the flag is blue, which contains the 12 pointed sun. Each sun ray is 30 degrees, so the total sun rays will make up a complete 360 degree circle. Inside the sun, the blue ring is the diameter of the white sun divided by 15.

In later years, more details regarding of the canton area (also used as the flag of the KMT), were codified into law. In the drawing released in Act on the Party and National Flag Manufacturing and Usage Methods (黨旗國旗之製造及使用辦法), the sun was drawn in more specific detail and mathematical values were given to all elements in the flag. In the law, the canton still had a ratio of 2:3, but the math values given were 24 × 36 meters. The diameter of the sun with rays is 6⁄8 of height of the canton, so in this case, it will be 18. The diameter of the white sun without the sun rays is 1⁄4 of the width of the canton, so it is 9. The blue ring that is on top of this sun and part of the rays is 1⁄15 diameter of the white sun, so the size will be 0.6. The angle of the rays, 30 degrees, and the total number of rays have not changed.

The colors of the national flag are dark red, white and dark blue. However, the KMT party flag only uses white and dark blue; both flags are to be topped with a golden finial. The law does not list any specific color processes, such as Pantone, to manufacturing or drawing the flag. The Ministry of the Interior provides colors only for reference. Other publications, such as the Album des pavillons nationaux et des marques distinctives, have given approximations for Pantone colors: the dark blue as Pantone 301 C and the dark red as Pantone 186 C. Album des pavillons also gave the approximate CMYK colors for the flag; dark blue is 100-45-0-10 and dark red is 0-90-75-5.
The colors approximation in other color spaces are listed below:

In the early years of the Republic, under the KMT's political tutelage, the flag shared the same prominence as the KMT party flag. A common wall display consisted of the KMT flag perched on the left and the ROC flag perched on the right, each tilted at an angle with a portrait of Father of the Nation Sun Yat-sen displayed in the center. For the summits held between the KMT and Communist Party during the Chinese Civil War, the ROC flag was displayed at an equal position to the flag of the Chinese Soviet Republic (Jiangxi Soviet). Later, the flag law specified a horizontal display of the flag with the portrait of Sun Yat-sen in a portion of the red field at the center position. This display can be found in numerous government offices in Taiwan and is that which the president and vice president face to take the oath of office.

The flag has a ubiquitous presence in Taiwan. The hoisting and lowering of the flag are ceremoniously accompanied by the National Flag Anthem of the Republic of China while those present stand at attention to give a standard salute with the right hand, held flat, to the right eyebrow. Schoolchildren have traditionally been required to attend morning rallies where the flag is raised after a rendition of the National Anthem of the Republic of China. Before martial law was lifted in 1987 in Taiwan, it was required that all vehicles be halted when passing by a flag ceremony.

Instead, the ROC is usually represented under a pseudonym (usually "Chinese Taipei").

The symbolism of the ROC flag began to shift in the early 21st century as there was a warming of relations between the pan-Blue coalition in Taiwan and the Chinese Communist Party on mainland China. The flag of the Republic of China has begun to symbolize a common shared history between both mainland China and Taiwan, and as such the government of the PRC has made it clear that for Taiwan to change the flag would be a major provocation in favor of Taiwan independence. The ambiguity surrounding the flag was made apparent during the trip of Kuomintang Chairman Lien Chan to mainland China in April 2005, during which the flag was very prominently displayed at ceremonies honoring Sun Yat-Sen at which both KMT party officials and government officials from the PRC were in attendance. One place in mainland China where the White Sun emblem is still prominently displayed in public is the ceiling mosaic within Sun Yat-sen Mausoleum in Nanjing.

The use of the flag in Taiwan reflects the controversy behind its symbolism. Although supporters of Taiwan independence, such as former president Chen Shui-bian, will display and salute the flag on formal official state occasions, it is never seen at politi…

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