In Japan, from the 3rd century to through the 6th century, dwelling houses of the ancient burial mound period diversified in form and construction technique. No longer contented with the thatched pit houses, homes and residences grew in size, added timbered walls. The Kofun Period people even built upwards with more storeys. Houses of the previous era, excepting grain storehouses, were mostly subterranean, but now raised-floor houses became common dwellings too. Some houses were positively palatial and grand for those times!
Better equipment and techniques of building, as well as a sense that private dwellings could be symbols of social status, led the people of the Kofun age to experiment with their buildings and homes. Few buildings of the Kofun age are left today because people began to build homes with raised floors, so that there were no longer the post holes of the pit homes of earlier periods to mark their settlements. However, we know their buildings looked like from the art left behind on bronze mirrors and haniwa earthenware models of buildings of the tumuli.
While commoners continued to live in pit dwellings similar to those of the Jomon and Yayoi eras, important and wealthier people built larger and even multi-storied buildings for themselves, often in fenced-around compounds that separated the ruling elite from the common people. Palace-like residences came to be built as royal estates were being established during the Kofun age not only in the city or town centers, but also in the outlying provinces.
But the raised floors used in storehouses became incorporated into the residences of local chieftains and other high-ranking persons. The raised floor dwelling became a mark of social status for Kofun people in western Japan and the Osaka area. Decorative features of architecture diversified taking on many experimental forms.
In the Kanto and eastern areas, the ground-level dwelling was more popular with people of rank and status.
The storehouses or warehouses that had appeared in the earlier Yayoi period remained important architecture in the Kofun age. They remained mostly in the same style, but larger warehouses were seen in the areas controlled by the royal rulers and chieftain kings.