Typical breast star of this type.
Case.
Rosette.
This type of construction was introduced by Japanese Mint in the late 1970s (somewhere around 1979) together with two-letter marks https://asiamedals.info/threads/two...it-marks-on-japanese-orders-and-medals.13720/
Before 1979 breast...
2ndclassorderofthesacredtreasure
modern orderofsacredtreasureorderofsacredtreasure variations
orderofthesacredtreasureorderofthesacredtreasure breast star
orderofthesacredtreasure trident breast star
勲二等瑞宝章
瑞宝章