Yokoguchi-shiki sekkaku was originally a stone coffin which was placed in a rock chamber and the stone coffin itself became a mortuary space; many of this type can been seen at the end of the Kofun period.
横口式石槨は、本来石室内に置かれていた石棺が単体で埋葬施設となったもので、古墳時代終末期に多く見られる。