It's not Japanese, it's a French Lebel bayonet
47th MP Co/47th Inf Div 1983-1988
583rd Ord Co 59th Ord Bde Muenster, W Germany
Looking for P37 ammo pouch with No4 bayo frog
It's a French Lebel Bayonet...Pure speculation on my part, but possibly taken from the Vichy French in Indochina...
Thanks guys! That explains why I couldn't find it under Japanese bayonets anywhere
Here are a couple links that I have found handy over time ...
Bayonet Identification - Identify Bayonets and Related from Selected Countries