Hand Signs

Seals (印; English TV "Hand signs") are used to create many Ninjutsu, Genjutsu, and other secret arts other than Taijutsu. 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 Blast Technique, which requires a total of 44 hand seals to activate. Tobirama Senju, the Second Hokage, however, just needed to use one hand seal to complete the technique, a testament to his skill.

Basic Seals:
There are twelve basic seals, each one named after an animal of the Chinese zodiac.

子 (Ne, The Rat), often used in the Nara Clan's Shadow Jutsus
丑 (Ushi, The Ox)
寅 (Tora, The Tiger), as the last seal of the sequence, it is indicative of Fire Release jutsu
卯 (U, The Hare)
辰 (Tatsu, The Dragon)
巳 (Mi, The Snake), as the last seal of the sequence, it is indicative of Earth Release jutsu. It is also used at the end of Wood Release jutsu, likely because that uses Earth nature chakra, together with Water nature chakra
午 (Uma, The Horse)
未 (Hitsuji, The Ram)
申 (Saru, The Monkey)
酉 (Tori, The Bird)
戌 (Inu, The Dog), often used in Ice Release by Yukigakure ninja
亥 (I, The Boar)

Other Hand sealsBesides the twelve basic hand seals, there are unique hand seals used for certain techniques. These hand seals are rarely seen, and can be considered unique to specific jutsu. Examples are the seals used for Haku's Demonic Ice Crystal Mirrors, the seal used for the Yamanaka clan's Mind Body Switch Technique, and the seal used for the Shadow Clone Technique.