Hand Seals

Seals (AKA Hand Signs) are used to perform many ninjutsu, genjutsu, and other secret arts other than taijutsu. Invented by Indra Ōtsutsuki, they are designed to aid people in properly summoning and molding chakra necessary to perform a technique. There are different sequences of hand seals for every technique, requiring memorization.

While techniques may require a number of hand seals to work, a skilled ninja can use less or even one to perform the same technique. An example of this is the Water Release: Water Dragon Bullet Technique, which requires a total of 44 hand seals to activate. Tobirama Senju, the Second Hokage, only needed to use one hand seal to complete the technique, a testament to his skill. In fact, by Part II, Sasuke Uchiha has managed to master the Chidori to the point of not needing a single hand seal to invoke it and could use Fire Release techniques with only one hand seal. By reading the hand seals of the opponent, a ninja can predict the nature of the technique to be performed, which is virtually unavoidable if read by the Sharingan.

Although rare, it is possible for a shinobi to be able to do hand seals with just one hand. Shinobi seen capable of this are Zabuza Momochi, Haku, Itachi Uchiha, Fudō, Guren, Minato Namikaze, Naruto Uzumaki, Sasuke, Deidara, Sai, Shizuma Hoshigaki, Ryōgi, Ao, Boruto Uzumaki, and Inojin Yamanaka. It is also possible for shinobi to form hand seals with one of their hands while using the hand of another person as a substitute for the opposite one. This can happen voluntarily, like when Naruto and Sasuke joined hands to dispel the Infinite Tsukuyomi, or forcefully, such as Anko Mitarashi using Orochimaru's hand for the Twin Snakes Mutual Death Technique, or (in the anime) Obito Uchiha using Kakashi Hatake's for the Fire Release: Great Fireball Technique.

Even rarer than one-handed hand seals, are shinobi who have abandoned this traditional practice altogether, usually because their fighting style revolve around speed and quick reflexes and have developed techniques that require no hand seals to complement this fighting style.

Certain elemental releases often end in the hand seals they are affiliated with. For example, Fire Release often ends with Tiger, Earth and Wood Releases often end with the Snake hand seals. Teruko uses her Diamond hand seal in her all basic chakra nature techniques, for example, in Elemental Destruction.

Byakugan Seals- In the anime, certain variant seals to aid in the activation of the Byakugan are seen. Most are some of the basic twelve seals, but several are different. In the manga, seals are indeed used several times, but of course, they cannot be seen with detail.

Fuuma Clan Curse Mandala- In the anime, the Fūma clan used various unknown hand seals for their secret techniques, the Curse Mandala.