Yoshihito was the 123rd emperor, this traditional list included several nonhistorical monarchs. He was posthumously given the name, Taisho Emperor; called after the name of the era over which he presided, the Taisho Era (1912-1926). His personal name was Yoshihito and he was the third son of the Meiji Emperor.
Unlike his father the Meiji Emperor, he did not play an active role in Japanese politics. He was plagued by ill health, mental and physical. Shortly after he was born, in 1879, he contracted what now appears to be meningitis. His education, such as it was, stressed physical training rather than academics. However, he was the first heir to the throne to receive a public education, attending the Peers School (now called Gakushuin University), studying Western subjects as well as the Chinese Classics. He started formal schooling in 1887 and attended for eight years. After that, he was privately tutored in Western and Chinese subjects.
Always regarded as somewhat mentally impaired, he did ascend the throne on his father’s death in 1912. By 1919, however, he was unable to undertake such official duties as presiding over the opening of the Diet. (This should not have surprised anyone since he was seen making a telescope out of a speech he was to read opening the 1913 Diet. He then gazed through it at the Prime Minister, his government and the opposition.) He spent more and more time away from Tokyo at various imperial retreats. In 1921, his son, Crown Prince Hirohito (the Showa Emperor) was appointed Regent. He served in this post until his father died in 1926.