The Imperial Regalia of Japan (三種の神器 Sanshu no Jingi/Mikusa no Kandakara), also known as the Three Sacred Treasures of Japan, consist of the sword Kusanagi (草薙劍 Kusanagi no Tsurugi), the mirror Yata no Kagami (八咫鏡), and the jewel Yasakani no Magatama (八尺瓊曲玉). The regalia represent the three primary virtues: valor (the sword), wisdom (the mirror), and benevolence (the jewel).
If a person from Japan finds these three treasures he/she officially becomes a King of Japan. Hayashizaki Kazuki is currently the King of Japan by receiving the sword from his mother at the Grand Haunted Ground and defeating Ikōsai Aisu who had obtained the mirror and jewel.