Showa-era school uniform: The "Chu-Ran" (Mid-length Ran)

There are no major stains or tears, but please be aware that this item is 45 years old.
The iridescent fabric on the inside is best represented in photos 1 and 2.
There is a keyhole near the hem.
There are four buttons on the sleeves. Please see photos 5 and 6.
I hope you like it! (*≧∀≦*)