My Father-in-Law gave me his WWII bring back type 14 Nambu. It was beautifully made and accurate. It had the best trigger I have ever seen on a military sidearm.
Their pre-war rifles were also fine firearms. As the war drug on, the quality declined.
I do agree with the odd number types of ammo. I think there were several different types of their .31 caliber ammo. Some for one type of machine gun, some for another and some for rifles.
You are lucky, my dad sold the one my uncle brought back from the pacific. He said the side bar was much too dangerous. According to lore, it was used to fire the weapon when handed off in a ruse surrender.