The 3rd earliest period in Japan is the Kofun period. It goes from 300 CE to the 6th century. The Kofun word refers to the huge burial mounds for important rulers at the time such as clan leaders. There is a high concentration of these in Osaka/Nara where Japanese imperial system starts. What are some of the things found in these tombs? Things such as pottery, gold, swords, armor, clay figures of horses, jewels, and mirrors called magatama. The mirrors have a connection to the Shinto goddess Amaterasu. These have political power, and are sacred objects that are a connection between humans and Kami. These crescent shaped jewels are now with the imperial family.
Not all of the Kofun tombs have been fully searched. The Japanese government hasn’t allowed the search because (some believe) that they will find Korean items or items that are not considered “Japanese”. Some believe that the past kings, before the end of the Kofun period were actually Korean or Chinese. Outside surrounding these tombs are clay figures called ‘haniwa’. These clay figures are of people, animals, horses, boats, etc. There are theories that these are maybe used as caretakers for the dead or tomb markers. These are implanted around the tomb and can be several feet tall. The Kofun period ends in the 6th century with the arrival of Buddhism. Power is centralised and one clan, the Yamato clan rises to power. Also cremation becomes popular.
Giant Kofun tomb, the Daisen Kofun in Osaka: