Hello Dieter3,
I do agree with you, however, the Allied Victory Medal for Japan fits in so many collections. Collectors of Japanese, WWI in general and WWI Allied Victory Medals of the world could find this medal an interesting addition to their collections. Even with this there always seems to be the Japanese Allied Victory Medal offered for sale and that, of course, only serves to fortify your point.
I have a copy of Vernon's Collectors' Guide, Fourth (Revised) Edition and he lists the WWI Allied Victory Medal for Japan at $350.00 and that is not taking into consideration whether it has the original case or not. Yet the 1914-15 (WWI) medal lists at $125.00 and the later issue, the 1914-20 is $75.00. I have found this guide to be pretty close to the prices asked by one of the local dealers here but anything I have purchased through on line auctions I've gotten for a lot less.
I thought I would offer this to this discussion for what it is worth.
Regards
Brian