Japan- 2 Shu Manen era

This is for the Japanese experts.  Let's see if I did it correctly:


Metal: Au+Ag
Weigth..: 0.79 g
Diment.: 7.0 x 12.2 mm
Tickn....: 0.95 mm

https://en.numista.com/catalogue/pieces69472.html

From the specs and looks of it you did right with your identification . I can't say much about the authenticity (haven't handled japanese gold yet myself) but its the 2nd least valuable type so the chances of it being real are high.

Nevertheless a great little coin to have in ones collection