Katana is considered a cutting tool and is subject to legal jurisdiction. Therefore, its complete legality. In the United States, you must be at least 18 years old or obtain explicit permission from your parents to own Katana. Whether you can carry a samurai sword outdoors depends on your state of residence, and we suggest that you check the laws of your state yourself. Generally speaking, carrying swords in public is prohibited and must be carried in dedicated bags or safe boxes.