Fūinjutsu, or sealing techniques, is a form of ninjutsu used in the Naruto series. It involves creating seals to contain, restrict, or manipulate objects, chakra, or even living beings. These techniques can be used for various purposes, such as sealing away dangerous entities or storing items for later use. The effectiveness of Fūinjutsu often depends on the skill of the user, with advanced practitioners like Minato Namikaze and Tobirama Senju demonstrating exceptional abilities. Seals can be inscribed on scrolls, surfaces, or even directly on a target, making them versatile tools in a ninja's arsenal.