When Amaterasu made a small opening in the rock, the mirror reflected her face, drawing her attention and successfully making her come out of the cave, thus bringing light back to the world.
天照大神が岩戸を細めに開けた時、この鏡で天照大神自身を映し、興味を持たせて外に引き出し、そして再び世は明るくなった。