In the coastal area of Genkai-nada Sea among other part of northern part of Kyushu, earthenware jar-coffins which were buried together with as many as twenty to thirty mirrors can be found in remains such as Sugu-Okamoto and Mikumo remains, which tells us how luxurious kings' graves were.
北部九州でも玄界灘沿岸の地域では、須玖・岡本遺跡や三雲遺跡などで20枚とか30枚もの大量の鏡を副葬した甕棺があり、王の墓の豪華さが分かる。