Then, from the middle to end of the fourth century, in a fifty year period, four large keyhole-shaped mounds of the 'okimi' (great king) class in scale of size were built in the Saki (also pronounced, "Sofu") region of the Northern Nara Basin.
4世紀中頃から末までの半世紀の間に奈良盆地の北部佐紀（ソフ（層富）とも）の地に4基の大王墓クラスの前方後円墳が築かれる。