Looks like 100% Chinese Tiger to mee
Does the plain reverse without any marks indeed indicates that piece was made in Japan?
I don`t think so.
There are pieces without any marks that are definitely made by the same workshops that made marked one.
But let`s discuss this 2nd class.
The only "eccentric" features are
1) two riverts construction of the breast star
2) rear of the sashbadge has a red enamelled medaillon
Are these features really eccentric?
Well, check out piece that was shown in posts # 29 and # 30.
No marks and four riverts construction
Here comes another one ...