There are a variety of theories including that they imported the guns from abroad through Sakai region, that the guns were locally produced, and that craftsmen were invited from other areas as they did not have the technique of producing guns at the times.
説としては、堺より外国から移入した、地元で作られた、当時は鉄砲作成技術はなく他の地域より職人を招いたなどが言われている。