Post－World War II debate over the revival of Kigensetsu (see kigen; now known as Kenkoku Kinen no Hi, or National Foundation Day) as a national holiday. There had always been an argument as to the validity of dating the founding of Japan from the legendary enthronement of Emperor Jimmu in 660 BC. In 1872 the leaders of the new Meiji government had officially adopted this dating. By declaring in 1873 that the 11th of February would thenceforth be a national holiday to commemorate the founding of the Japanese empire, they hoped to give further legitimacy to the imperial institution. In 1948 the kigen system of dating and most traditional holidays were abolished; Kigensetsu in particular had come to be associated with the 《emperor system》 and with the excesses of nationalism during the pre－World War II period. Therefore, when Prime Minister Yoshida Shigeru advocated the revival of Kigensetsu in 1951, there was strong opposition, especially from leftists and intellectuals. Nevertheless, in 1966 a bill was passed declaring 11 February a national holiday, Kenkoku Kinen no Hi.