Just found one of these from a random toystore in Kuramae, Tokyo. Didn't know what it was but saw the seal and thought that why not. Came here for information and you guys delivired, thanks!
Just got back home and opened the package and actually I think this dama feels really nice. It's a bit on the heavy side, just like I like it (69,7/ken, 75/dama). The birch has a nice rough feel to it.