Fūinjutsu

are a type of jutsu that utilized written symbols instead of, or in addition to, hand seals. Most of the time, these symbols must be written in ink or blood, but on occasion have been known to be placed by pure chakra manipulation.

The most common uses for fūinjutsu seem to be explosive tags, summoning techniques, as well as storing objects in scrolls. Many fūinjutsu seem to be self sustaining, requiring no more chakra expenditure beyond the set up. The exceptions being those jutsu that need to be triggered, such as Hiraishin, and Summoning.

Fūinjutsu are also often used to bind or restrict things, most notably chakra, jutsu, demons, or other fūinjutsu.

The shinobi from Uzushiogakure in the Land of Whirlpools were specialists in the art of fūinjutsu, to the point that they were eventually destroyed due to the fear others had of their sealing techniques.