Hello,
I was thinking about this the other day and something jumped out at me.
My understanding is that kagami-migaki comes from Tenshinshinryo ryu and was incorporated into Judo's Tandoku Renshu by Kano Sensei as an attempt to pay some respect to the old ways. All I have seen of it is the pictures In the book Kodokan Judo by Kano copyright 1986 (Kano was long dead when it came out) and a few youtube videos probably based on trying to imitate the book.
Elbows flare out and there is no visible raising and lowering the torso.

Anyway I was thinking I had seen mirror polishing elsewhere and the I remember Marshall Ho'o's book Tai Chi Chuan the last of his temple exercises is mirror polishing. Once more I have the book and some youtube videos. Elbows are pointed down (essential for a Tai Chi movement) and the body definitely moves up and down.
My first guess would be just a coincidence. Mirror polishing is a metaphor for internal reflecting even in the west.
But is anyone in a position to clarify how similar or
dis-similar Kano's mirror polishing is to the original? Is the original allowed to be shown in public?

Does anyone know the origin of Marshall Ho'o's Temple exercises?

I am not asking anyone to divulge secrets but if this is information you are allowed to share I am very interested.
Thanks,

Len McCoy