The Iwatoyama Tomb is a keyhole-shaped tumulus which is 135 m in length. It is said to be a tomb of Tsukushi no Kimi Iwai. Many haniwa (terracotta clay figures) and stone standing objects (men and horses) have been excavated from an overhang called Bekku. This stone man is made of welded tuff of Mt. Aso and features a relief-like representation of a human body on a flat surface. Since stone standing objects, whose distribution centers on northern Kyushu, shift from realistic and three dimensional to flat ones, this one can be categorized as one of relatively new stone standing objects. It seems to have been created during the late Tumulus period around the early 6th century. On the front surface, a human face, a waist sash and a small and thin sword are represented in a wide hem robe with both arms up. On the back, an arrowhead is carved in the upper part, which suggests that it was originally a stone standing object in the shape of an arrow container, on one side of which a human body was carved. Since many of the stone standing objects excavated from the Iwatoyama Tomb are broken, those in their perfect original form like this one are very rare and valuable.