The mirror is a Mirror with an TLV Pattern and a Four Sacred Animal Design with an inscription, 'Seiryu Sannen' (third year of Seiryu, or 235) (Seiryu, or Qinglong is the name of the era of the Emperor Ming of Wei Dynasty of China).
鏡は方格規矩四神鏡で、「青龍三年」（魏の明帝の年号で235年）の銘がはっている。