Antique or Vintage Japanese Decorated Brass Sake Container

I bought this in Japan in 1970 in an antique store. I have looked online for something similar without success. The decoration is quite fine for what appears to be brass. Someone suggested it might be very tarnished silver. I used silver polish and rubbed quite hard on the underneath and it got somewhat lighter and brighter but does not appear to be silver. I wonder if anyone might have an idea about it, and how the decoration might have been applied. It's a more gold color than the body. Thanks for any information about it.