In various parts of the Asuka region are unusual carved granite stones the largest of which is Masuda no iwafune. This is a large stone structure approximately 11 meters in length, 8 meters in width, and 4.7 meters In height. The upper surface is flat, with a shallow trough and two square holes. This is located on top of a hill just a few hundred meters west of Okadera Station. How or why this colossal stone and others was carved remains a mystery. They appear to be a different style than later Buddhist sculptures. There are also several nearby kofuns or tombs including the Ishibutai Kofun which is built from massive boulders including one that weighs an estimated 75 tons. This may have been the tomb of Soga no Umako.