Bill, Teri, and I have been exchanging emails on this shotgun. There is also a US collector interested in details of it. There seems to be a Japanese WWII web site called 'Banzai'.
I don't know why, but I had not really noticed that this was a double-barrel shotgun. That makes the bayonet attachment much more complicated than I had realized.
I'm somewhat confused/amused that any nation expecting imminent invasion would bother fixing bayonets to any weapon.
Although I inagine the shotgun blast would make it easier to withdraw the bayonet...
