Yet, keyhole-shaped tumuli were found one after another in the southwestern Korean Peninsula after the introduction of Shokakudo No. 1 Kofun Tumulus, which is located in Kosŏng, South Kyŏngsang, the Republic of Korea, as one of them in 1993.
しかし、1983年に大韓民国慶尚南道固城の松鶴洞一号墳が前方後円墳であるとして紹介されて以来、朝鮮半島南西部で前方後円墳の発見が相次いだ。