Japan's birth as a nation, depending on the definition of nation used, could be as dated 10,000 years ago, when a hunter-gatherer society called the Jamon developed. Its birth date also could be identified as 710 A.D., when the first strong central government developed in Nara.
Japanese society in the eighth century was divided into clans, which were ruled from Yamato Province. When the samurai shoguns took over governmental power in 1185, a new type of Japanese nation was born.
Japan's birth date as a nation could also be considered to be in 1868, when the power of the ruling shogun lords was broken and a new constitutional monarchy was established. This new government was headed by the Meiji Emperor.