What are some of the guns used by the Japanese in WWII?

My friend said that his grandfather has one, but can not find anything on the Internet other than a person saying that the guns used in Japanese POW camps, including the list of military gear and equipment for the Second Japan in World War wikipedia dosent any list: (

Although lethal shotguns are not used and have not been commonly used for military purposes. It may be that the type of weapon to his friends grandpa owns a shotgun or similar is actually a shotgun, but it is unlikely that that was used by the Japanese military in WW2.

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