The Kofun period (古墳時代 Kofun jidai?) is an era in the history of Japan from around 250 to 538 AD. It follows the Yayoi period. The word kofun is Japanese for the type of burial mounds dating from this era. The Kofun and the subsequent Asuka periods are sometimes referred to collectively as the Yamato period. The Kofun period is the earliest era of recorded history in Japan; as the chronology of its historical sources tends to be very distorted, studies of this period require deliberate criticism and the aid of archaeology.
The Kofun period is divided from the Asuka period by its cultural differences. The Kofun period is characterized by a Shinto culture which existed prior to the introduction of Buddhism. Politically, the leader of a powerful clan won control over much of west Honshū and the northern half of Kyūshū and eventually established the Imperial House of Japan. Kofun burial mounds on Tanegashima and two very old Shinto shrines on Yakushima suggest that these islands were the southern boundaries of the Yamato state, while its northernmost extent was as far north as Tainai in the modern Niigata Prefecture, where mounds have been excavated associated with a person with close links to the Yamato kingdom.
Kofun (from Middle Chinese kú 古 "ancient" + bjun 墳 "burial mound") are defined as the burial mounds built for the people of the ruling class during the 3rd to 7th centuries in Japan, and the Kofun period takes its name from these distinctive earthen mounds. The mounds contained large stone burial chambers. Some are surrounded by moats.