Designed in 1932 by Ishii Mokichi, the founder of Shaken. [MrRifleman] Shaken mentions a 1970 date which might refer to a later version. [Shaken]
Contributed by Noah Rezentes
Contributed by Stephen Coles
Contributed by Patrick Concannon
Contributed by Jay Mellor
Contributed by thankyoucokieroberts
Contributed by MrRifleman