According to The Chronicles of Japan (Nihon Shoki), the goddess Amaterasu Omikami gave her nephew Ninigi-no-mikoto three celestial gifts, known as the three Sacred Imperial treasures (the Imperial Regalia of Japan): the sacred mirror Yata-no-Kagami, the sacred sword Kusanagi-no-Tsurugi and the sacred jewel Yasakani-no-Magatama. Ninigi-no-mikoto was the great-grandfather of the legendary Emperor Jimmu, the first Emperor of Japan, so these 3 objects are signifying that the Emperor is a descendant of Amaterasu.
The Yata-no-Kagami mirror is kept at Ise Jingu and is never displayed. However, every Shinto shrine has it own mirror (kagami) and in some of them you can even see it, like in his photo from Jishu Shrine, Kyoto (near the Kiyomizu-dera).
In the Shinto religion, the mirror is a symbol of Honesty, because it reflects everything…
Yesterday’s Japan Photo: