The Kofun period marked the appearance of many-chambered burial mounds or tumuli ("kofun" literally means "old mounds"). Similar mounds in Korean Peninsula are thought to have been influenced by Japan. Early in the period, the tombs, known as "keyhole "kofun"" or , often made use of the existing topography, shaping it and adding man-made moats to form a distinctive keyhole shape, i.e. that of a circle interconnected with a triangle. Access was via a vertical shaft that was sealed off once the burial was completed. There was room inside the chamber for a coffin and grave goods. The mounds were often decorated with terracotta figures called "haniwa". Later in the period mounds began to be located on flat ground and their scale greatly increased. Among many examples in Nara and Osaka, the most notable is the "Daisen-kofun", designated as the tomb of Emperor Nintoku. The tomb covers and it is thought to have been decorated with 20,000 "haniwa" figures.