Oriental Brass Disc - Origin, age, symbolism & inscription?

This is a 9.5" brass disc with 5 cranes on it that I acquired some time ago as part of a mixed lot.
I am wondering about symbolism and also what the inscription says. Is it Chinese or Japanese? How old is it?
The back is smooth with no marks on it.

 

Japanese where cranes are symbolic of longevity and good luck.

I can't read the characters but we do have a few members who may be able to.

 

The little rub wear at the bottom is probably from years in the frog's mouth!

 

or placed in a stand..

 

What frog?

 

u know....that frog !!!

 

I looked him up, the frog is Jin Chan.

https://en.wikipedia.org/wiki/Jin_Chan

 

Actually that's a break at the bottom with the piece soldered back in. I don't know how you break a small piece like that off but that's what it is.

 

LOL looks like some kid BROKE it out of Jin Chan's mouth!

 

I don't think it's wear. The disc is a casting, and it looks...to me...like a soldered repair, crudely done.

 

What would the purpose of this be? There are no attachments on the back for hanging.

 

Maybe a Japanese brass (or bronze) hand mirror with the handle broken off.

 

I think you're right. I googled that and found a similar one with the same 2 lines above the 4 cranes but no flying crane above and a different border. https://www.icollector.com/Chinese-bronze-hand-mirror-artist-signed_i10122497# When I look at the break at the bottom, there is evidence of grinding so that's where the handle was and that explains how it got broken.

Looking at several examples some refer to the inscription as a signature and when I use google translate, it comes up with "Tenka Tsuda Yoshinaga Kumahara". Is that a name? or what is it?

Most of the listings refer to bronze mirrors but this looks more like brass to me.